silentmouse:
I think that in these type of games, it’s part of the GMs job to screen for such things.
NowhereMan:
That said, yes, I have made it work elsewhere, and the main thing that has to be done to make it work is to vet your players (if possible) and to be very active in adjudicating any problems that come up.
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If you can earn the trust of your playerbase, where they know you'll handle any issues both quickly and fairly, things will go smoothly most of the time, and when you do hit turbulence, it can be dealt with decisively with the support of the players.
Agree with both of the above - it can work, but as a GM, you need to vet and develop your players and their understanding of what you're looking for in order to make sure that the games effectively self-regulates, and you still need to keep an eye out to make sure a few individuals don't dominate proceedings.
More generally, I think it depends on how well you set up the game and the central conceit/focus. If you consistently play as a party vs an opposition (i.e. with limited P v P) then min-maxing or godmodding isn't such an issue because everyone's pulling in the same direction, and the min-maxer's fun from making the most powerful character doesn't necessarily impact upon a more narrative player with a thematic build.
Re. NowhereMan's suggestion, I certainly remember that about a decade ago, there were a lot more games which had those large player bases (either in freeform or within systems) where that kind of thing happened - basically they were sandboxes where players were given space to push things forward and self-regulate.
Unfortunately, they did tend to suffer both because it put an awful lot of pressure on the GMs and Mods to keep everything in order and do the adjudication that you mentioned, and also because it tended to be impossible to get 30 players who were interested in the particular setting, wrote and posted at a relevant level and frequency, and were all largely on the same page about the general direction that the game was going in.
As such, you tended to either underpopulate in the first place, or suffer a massive player drop-rate because the story would inevitably be driven by those who either min-maxed the most or posted most frequently, which tended to drive other players away because they had less of a bite of the apple. That then became a vicious with the players who remained becoming more influential and often making second characters to make up numbers, which in turn made iteven harder for later entrants to make a mark and break in.
Ultimately, this is why I tend to prefer running and playing in smaller games - as a GM, you can vet your players more while shaping the world around them, you're under less pressure to do too much adjudication, and you worry less about having to moderate things like posting rates.