I wonder if you might want to figure out a way to expand the levels so they can still "go up a level" at the normal rate, even it it's just to 8th level. Consider that you could give them a bonus feat once or twice a level, like an interim level-gain. This would have the same effect as in a Mutants & Masterminds game, where the Power Level (PL) is the same, but the characters get more points: the numbers they can play with don't change, but they can do more stuff at the same level.
example: the fighter is level 6, picks up their appropriate feats/abilities; for the sake of argument, she chooses Two-weapon fighting. Then, when they earn the normal xp for level 7, you keep them at level 6 but give them a feat; even from a select list. the Fighter picks Improved two-weapon fighting.
...yes, I've just outed myself as unfamiliar with PFRPG's updates of 3.x. I've started reading the SRD and I like a lot of what I'm seeing for the PCs. I don't even know if this is viable, but it seems like it could be.
Basically, I'm referencing D&D 3e here, and what I know of it.
OPTION TWO: pick things that really devastate your style of gaming (low-level play; not going to say "heroic tier"). Theoretically, this should mean getting rid of certain powerful spells used by PCs and NPCs, while keeping in things that counter what monsters do that makes PCs need those spells.
My older example would be Wish, certain divinations, teleporting spells, flight and suchnot; basically whatever the PCs could use to leave the classic battle mat area, or auto-kill things, or auto-find items or places and skip the plot (find the path, I'm looking at you!).
OPTION 3: Another thing to do is fix the math of monsters so they don't need magic items to stay on level. I had an army of Fire Giants slain in a pickup game by one PC with a Chain and Great Cleave; and the lich who drove them in one shot. I had never done high level, so I didn't know that Monsters needed save-buffing spells just as much as PCs did. guh!
So yeah, I hear you on the Epic level front. I've got zero experience with it, so I don't really know how to challenge PCs with it.
I'm aware of issues with power attack and damage reduction (something about having enough plus to hit with strength and magic and feats, that you can ignore BAB and AC and just do damage after a certain level), but not many others. and I don't even know if PFRPG fixed that!
