Pathfinder: Boss Fights Only
I love the idea, I have my suggestions, but I think I'd probably want to express them in a present tense. I would ordinarily love to play in this type of game, but my RL is such that I have such unreliable web access, that I can only GM, and even then very lightly. I also have no experience in PF in terms of transitioning from beginner to novice. I am still in the former camp. I'd be hard pressed to write up the first three levels of any base class.
One suggestion I have, that worked for games I had in D&D 3.5, is loyalty points. Rewards that only add to new characters by existing players. It allows two things, death being a reward to veteran players, and thus an added cushion to the group in the encounter that player's character goes "all in" with tactic that throws all intentions of survival out, and only devastating the enemy as quickly and severely as possible. If a PC does this, other PC have some added protection, just by their comrade spearheading the suicidal tactic, especially if it's well planned prior.
In D&D, one example I saw was a retribution sorcerer. Every spell they had was tried to dealing damage through attacking with their weapon, or taking damage. Through Fireshield, Mighty Wallop, and many other enhancements they waded into combat. They also (this I think is not applicable in PF) used teleport and planeshift offensively; whether by teleporting magic items off foes, or sending them into elsewhere to be tracked (with scrying and locate creature) later. Also using teleport to reposition the group into key formations. The result was this constant nuisance, and only added enhanced by their familiar also having imbue familiar with spell ability, ready to flank and cast without concern for its own safety.
My players had an occasional desire to switch characters anyway, and while it seldom occurred, sometimes, like above, it was dramatic when it did. In the above example the character was hellbent on being a vassal of the Archons in Heaven, and felt only in death could be be of true service. So it was justified both by the player and character.
The concept is that death adds a dynamic, rather than speed bump. It's still costly early on, but later on it can be tactical choice by a character, and reward for the player. For us, loyalty points gave additional points to ability scores, max ranks that could be put into class skills (which is inapplicable for PF) and a portion of the old character wealth being transferred to the group (which was group boon) and part of the remaining added to the new character; wehile the rest was claimed by...in the above cases a herald of the Archon Lord. Death bring with it new life. I'd not overlook the material wealth provided by a PC death. This can be major factor in strategy, and should be rewarded, but limited, to prevent abuse. ←THIS is why making a duplicate "new" character is subpar. At least most of the time (in games I've been a part of, at least).
Please feel free to contact me if you feel the urge to. Best of luck! It looks like an excellent game!