I'm just happy if they get the basic combat mechanics right for once; spells, monsters and such you can rework easily enough but basic combat mechanics (in the case of PF, the abomination that is full attack, the silly high speed casting where spells are generally faster than attacking, ability to completely circumvent melee threat by walking around it due to turn structure, etc.) are so deeply ingrained the system (lots of feats and such work off it) that reworking those entails reworking the whole system at which point it's more economical to just make your own, which nobody will bother to learn except for maybe that one guy at your table leaving you with one game at best to work with.