Sorry for taking so long to reply to this, but I've been busy and haven't had much time for writing.
I'm not sure how well it is written, but I hope it answers your question.
JohnStryker:
DarkLightHitomi:
Thus the thing I dislike the most though is the notion that a system can be played in only a very limited number of ways, and I believe this notion is the reason behind a lot of issues, arguements, and complaints about rpgs.
I think D&D in particular has a lot of aspirations that it doesn't directly encourage through its mechanics, so that if you forget that you read those more philosophical paragraphs and just become experienced that playing the game, it's at its most effective modelling that more traditional, competitive, gamey mode of play. Yes, it's robust enough that the system itself is a tool for many modes of play, but it also heavily rewards narrative progress and paints the DM (even by implication of title) as a "master antagonist" figure. Intentionally or not there's a lot of encouragement at a fundamental level to approach what we're calling "traditional" play.
That said, 5e really starts to put its money where its mouth is in beginning a gentle shift towards that more shared-plot-centric approach.
I don't know Fiasco, but I'd love you to unpack where you see character agency as a focus on a mechanical level in D&D a little more - I might be missing something there.
Edit: No sarcasm there - I'm genuinely interested. It's hard not to sound smarmy in type.
Much of my belief that character agency is the goal isn't from what any particular mechanics, but rather comes from a holistic view of the system, advice in the core books, and from the writings of Gygax and a few others (such as a firsthand account od the first dungeon delve, using chainmail at the time). Also, I don't believe that DnD is more supportive of traditional gameplay, rather it's simulationist nature works against traditional gameplay, yet because of the all the mechanics, people tend to see it as being a flawed game geared for traditional play.
To start in unpacking this, we need to first look some terms. I would place some general catagorizations to the various styles.
Gamist style, or perhaps Munchkin style might be a better name, is focused on having mechanical growth (whether from a single unit gaining power, from gaining more units/resources, or from arranging resources in an advantageous way), and overcoming clearly defined obstacles, aka winning.
Narrative style, or collaborative storytelling, is focused on telling a good story, and often involves the players wanting to have as much say in how the story goes outside the characters as the GM, even presenting ideas for things that happen to their characters that the characters themselves would not choose, especially often making choices based on what sounds good story-wise and would never intentionally make a choice that brings the story to a premature end.
Agency style is where the focus is on what the character knows and making decisions that the character would make. This is like pretending to be someone else for a day. If you were a [something], what would you do? This is also about exploring things from another's point of view. This is also the most like an interactive book. The gm plays destiny (as in "you meet your destiny on your way to avoid it.") and the players don't know what is happening beyond what their characters know and simply have their characters respond to wha tthey percieve (something both munchkin and narrative styles lack, as munchkin has a major focus on using metagame knowledge to make decisions, even if avoiding metagame knowledge about the story, and narrative has the player standing back and having a say in what happens to their characters).
Social style, the focus is less on the game or handling the game in a particular way, but rather having something to do while joking and messing around with each other. The beer and pretzels games, like Kobalds ate my baby, fit here.
Supers style, this is all about doing cool things (like swinging from chandeliers) and/or feeling powerful. In this style the focus is on feeling cool and powerful based on what happens in the game. casting a spell and having an army keel over dead make sone feel powerful, and players will seek and desire to do things that make them get that feeling of power or that makes them feel cool. Cinematic action basically.
These are of course not discrete, but rather points on a continuum. Traditional gameplay style is mostly munchkin with some supers style.
Now that we have some terms to reference, we can address a core misbelief. It might even be a fallacy of some sort.
I've been told by many players something to the effect of "if you want a game about the story, play free-form." These players are equating the mere existance of rules with a focus on munchin/supers play.
This is however an unfair association and is based on a false belief. The false belief is the idea that if story trumps rules then rules become meaningles and therefore should not be included (excluding table rules, rules baout behaviour at the table).
Rules can be beneficial for any style of play as play aids, even when not essential to the game itself. For collaborative and agency styles of play, rules fill the purpose of aiding in communication, understanding, maintaining consistency, and providing a shorthand for descriptions.
I.E The system gives a shared method of describing just how strong a character is that gives all the players similar expectations about how strong any particular character really is. Without the system for that, you are left with each player trying to describe a level of strength with every player having different ideas about what "very strong" means.
This means the system makes it easier to discuss characters and actually have everyone on the same page about what each character can do. It also means that the GM can use terms and values defined by the system to make it easier to describe aspects of the world or situation, particularly for information that the players wil always want to know, which leaves more time for for describing the purely fun stuff and adding the appropriate thematic feel to the descriptions with less worrying that someone might get the wrong idea about somethig essential (which will happen, but the system reduces this).
In fact, agency and narrative style play can benefit from rules but are actually distinct from the rules entirely, allowing you keep playing even as rules change or even as changing from one system to another (though different systems can be used with differing levels of ease). The rules in these cases are mere play aids and nothing more.
One thing some players may mention is how much the rules focus on combat, implying that the game is obviously about combat since there are so many rules for it. Modern game design has some understanding of the fact players will be affected by prompting from the rules (as in, if the rules say how to do A, but not B, then players will almost always pick A even if B is available or even superior). Psychology is a major factor in life, and games can be designed with psychology in mind (for evil and terrible results as much as good). DnD and many other games though were not designed with an understanding of psychology, thus even simple things like "more rules = focus of game" can be mistaken.
The rules of DnD has more rules on combat for many reasons, one of which is certainly the history of the rules being based on wargaming rules, but also because combat is one case where agency comes to fore (in your choice of tactics, whether you fight directly with honor, fight dirty, fight smartly, or fight just enough to get away) in a way that is easily handled mechanically yet also requires more depth to remain interesting.
How do you make generic rules for resolving social conflict, convincing a merchant to give a discount, win a court case, sell your product to the king, etc. Much more difficult than mechanically handling combat, and even when it is done, it takes away from the roleplaying of those things and also, many of the benefits of using mechanics (such as consistency) do not apply to such social circumstances. Many players take this to mean that DnD is all about combat, but that isn't true.
There are many types of balance. Mechanical balance is often the most discussed and most recognized, but other kinds of balance exist as well. DnD has more naturalistic balance, which indicates that munchkin style is not a core design goal, as munchkin style almost requires mechanical balance, and given the birth in wargaming, if mechanical balance was a goal (as it would have been if munchkin style was a goal), then Gygax et. al. would have had much better mechanical balance and not naturalistic balance.
Interestingly, the DMG mentions balance, but it isn't really balance in the normal sense, rather it is mentioned as three things, 1) making sure that no one character dominates over the others, 2) having characters not be too powerful for the threats they face, and 3) not be hopelessly overmatched. Of course, these don't require mechanical balance, and in fact, I'd say that being able to step away from mechanical balance would be important for these aspects. I have played characters several levels behind others without feeling underwhelming or like a mere squire or servent to the other characters. Being too weak or powerful for encounters doesn't require facing all equal level encounters either, and in particular, the player's combat styles are important here, for example, if a player is awesome against single targets, ganging up on them should be a weaker encounter mechanically because they have less ability to handle multiple foes, and when they face a single foe, having the foe be higher level might be required for them to actually be challanged.
While I don't know much of older editions, there are some things I know of that were not popular and thus altered, but they give insight into the thinking of the designers. The biggest of these was xp = gold. This was a really good concept (though I'd like to think I've done better). The idea behind this is not that picking up gold is worthy of giving you xp, but rather that the xp represents everything you went through to get that gold. This is actually very good because it doesn't distinguish
how you got the gold, therefore giving you freedom to play through the game according to character and/or player preference without feeling like you are losing out on xp because you sneak around enemies or escape a fight rather than kill.
Killing for xp is a step backwards because it only rewards winning a fight rather than rewarding reaching the goal. However this is in place most likely because of the negativity around gold = xp rule, which I hear many believe to be very stupid.
A major part of my thoughts on the system though come from a holistic view of the system, rather than discrete parts, particularly since the books don't seem to have been written very well. In fact, there are several points where the author's descriptions are so poor as to seem like they contradict the rules, though in restrospect, the line of thinking can be usually be found. Alignment is an example of this (lawful is about unwavering dedication and being methodical). This means care must be taken to consider the different possibilities of what the author could have meant by their descriptions.
Random character stats is another point against munchkin and supers styles. Munchkin style is fairly competative, hence the need for point buy to make certain that all players start equal and thus rely more on player skill and ability. On the other side, random character stats provide unknown talents and weaknesses to a character, promoting character exploration and providing interesting obstacles to overcome and interesting talents to take advantage of.
The gm's and player's role are also laid out, discounting the collaborative story telling style, as it is the GM's job to set the scene and describe the action, while the player dictates the character's personality and decisions. Importantly, to quote "be true to your character."
The biggest consideration however, in why DnD is about agency is several paragraghs that generally get ignored and remain unused (and likely unknown to anyone who hasn't actually read through the entirety of the core books, mostly the dmg). These paragraphs are the ones scattered around encouraging the bending, breaking, and rewriting of rules based on characters and circumstances (as distinct from fixing things you think are wrong/bad/boring). For example, the gm is encouraged to allow a paladin to swap out their mount for a different ability if their character concept doesn't include a mount or would rarely benefit from that ability. There are many spots encouraging not houserules, but gm rulings that allow things breaking the normal rules to fit the situation.
This is an essential point, because this encouragement actively works
against the traditional style of play.
A particular quote that can't be said enough "The GM defines the game." I always consider the GM to be the single most important part of the game because they control the experience. If it's bad, it because the GM was bad. If it was great, it is because the GM was great. The fact that the DMG specifically states this means the authors recognized this. Strangely enough, I have met more than a handful of players who don't know this yet, surprising as that may be.
On the same page of the DMG is this quote "You are the master of game -
the rules, the setting, the action, and ultimately the fun." Emphasis mine, but notice that the rules are specifically called out as the GM's domain, not the domain of the game.
The GM is also told to make the world feel alive so that the players feel a part of the world instead of separate from it. Traditional gameplay often breaks into the meta side of things (particularly for hardcore players that think arcane casters are for idenfying potions). Narrative, and Munchkin play in particular, are both styles where the player is heavily in the metagame, watching their characters yet distinctly divorced from their characters on some level.
Another example is that the book has the GM have the players think in terms of the game world, using the example of a trap in a dungeon existing for a reason and having served a purpose and thus to encourage players to think about why that trap exists and thus how it might be bypassed.
Railroading is called out as being bad, but when it comes to munchkin or traditional style games, they usually run better when railroaded, as the focus is on the metagame of winning rather than story changing choices, and therefore, those styles lend themselves well to a GM running players through a railroaded story, much like playing through a linear or semi-linear video game (The Halo series, Pokemon, RTS campaigns, FPS campaigns, well just about any video game really, even Mass Effect and Fable, both games targetting the concept of player choice are rather linear railroads with choice being illusory and maintained through minor details). This is actually probably the best style to target for a GM that wants to tell a story. (far too often do I see a GM want to GM so they can tell their awesome story only to get frustrated as the players constantly break the story.)
But for a style centered on character agency, railroad is the worst as it removes the primary focus of the style.