Think you're right back on the same track again, me bucko.
I think some groups just need to sit down, open up the PHB and use ONLY THAT. No house rules, no special rules, no outside classes, no outside feats. NOTHING.
Play the game as written. That's the best suggestion I can think for a group like that.
If people aren't hot and bothered to play Favored Souls and Half Dragons and the like, maybe you can get some more of the core concepts walking in one direction together.
If the GM isn't jerking you around with half-baked house rules, then you can play characters that have the stuff at their disposal to meet the expectations of published modules.
Because the published modules are built on an assumption of the core rules.
And proper use of those rules, as well. I.E. not making up half-baked situations improperly applying rules.
If it were me, I'd be starting my own campaign. But I like running games, so, maybe I'm a bad model.
To be honest, my feelings are that the root of the problems are with the GM. A bad player can be delt with, you can let the guy with the dippy Ranger get his character killed off a few times and he'll wise up and stop it. But there's not a whole lot that can be done to save a game if the GM is going to run a published adventure path while applying a whole bunch of punative house rules to pretty much ASSURE that the characters will not succeed.
--fje