I wouldn't go so far as some of you are going, of course PF had troubles, but a lot of the propossed changes are extremely drastic.
Overal.- would reduce the effect of size modifiers for combat maneuvers, as it stands the maneuver system overtly benefits monsters. It has to be tonned down.
Feats.- reinstate feat chains back to 3.5 levels, (improved maneuver familiy I'm looking at you) reinstate the bonuses to their original values and make them scale by bab.
Weapon specialization scales by bab
Feats like spell focus, spell mastery and the like require you to be specialized in that school.
Skills.- Remove the perception skill, every instance of it becomes a raw wisdom check. Trapfinding now adds full rogue level to wisdom checks to find traps. If you want to be better at perception, invest on feats, traits and a better wisdom.
Outright state that different Perform skills can substitute for other skills when trained as something everybody can do.
Spells.- Modiffy all buff spells to only work on people other than the caster by default, specialists can use spells of their school on themselves. Overall reduce the power of spells across the board to fit with the skill system, but let them have the power to break it in the hands of an specialist. (for example Arcane lock closes a door and increases the open DC by 1 per spell level if it has a lock, only an arcane lock casted by an abjurer or a sorcerer can produce the full effects of an arcane lock. Equally Knock allows an untrained disable device with a +1 to +9 bonus, but a diviner outright opens the lock) Scrolls by default always use the weaker version of the spell.
Introduce Legendary scrolls which can have the full version of the spell, but cost one hundred times more to make and take twenty times as much, they need Scribe Legendary Scroll (a new feat with scribe scroll and 10 spellcraft ranks as prerrequisites )
Magic items.- As told before, wands and scrolls can only have the weakest possible version of a spell, wands cost the same to be made, but are created with only twenty charges.
Change the standard magic weapons system. Swords can no longer have a clean enhancement bonus, (but masterwork bonus applies to damage), only properties, the system to calculate the cost of properties remains the same. Introduce the "enhanced" property which adds a +1 bonus to damage and attack but costs +3.
Armor and shields work on asimilar way, the masterwork quality improves the AC bonus by +1, again they cannot have enhancement bonuses, only properties.
Bracers of armor, rings of defense and amulets of defense cost twice as much and are capped at +3, they don't stack between themselves but stack with regular armor and shields.
Duplicate the costs of the cloak of resistence, reduce the cost of all items in that slot by 20%.
Change the cost of mental plus items, move it form quadratic to cubic.
Classes:
Across the board.- everybody but wizards, clerics and druids gain +2 extra skill points per level
Bard.- reinstate the original performance system, changing rounds per day to uses per day, increase uses by 50%. Allow them to treat all perform skills as if they were trained. Masterwork bonus and bonuses to perform skills also apply to bardic performance DCs.
Cleric.- organize all spells into domains, if you deity doesn't have that domain you can only cast spells form third level or lower from that one. Deities also have forbidden domains.
Druid.- Druids must pick shapeshift forms as they grow in level, no more picking whatever fits from the bestiary.
Sorcerer.- Reduce their maximum spells known by 1. They treat all of their spells as if they were specialists.
Wizard.- reinstate the forbidden school limits, no more casting spells from your banned schools. Reduce skill points to 0+int. Universalists don't have to ban schools, but they lose access to the strong versions of all spells and key feats which require specialization. No more UMD.