My list of what I'd like to see:
1. Non-biological racial abilities turned into feats
2. More starting hit points
3. Action Points and Healing Surges, but I prefer Mutants and Masterminds hero point approach. Hero points allow a reroll and if the die roll is 10 or less, you add ten to the roll. In addition to rerolling, action points can be used for a variety of other effects including healing surges, duplicating a feat, taking an extra action, etc.
4. Unified Saving throw: And, to prevent multiclass abuse of stacking class bonuses, you only receive a saving throw bonus from your initial class. Otherwise take feats like Iron Will and Lightining Reflexes.
5. Armor and Weapon Proficiency: The armor and weapon proficiencies granted by class are only granted to first level characters. After first level, a character can only acquire proficiency in armor or weapons via feats (including class bonus feats if the armor and weapon proficiencies are on the list of bonus feats).
Edit:
6. No XP cost to create items: Replace Item creation with Artificer's Handbook (Mystic Eye Games)
7. No XP costs to cast certain spells: Use Pathfinder's method
8. No Level Drain
9. Passive Perception and opposed skills: DC 10+opponent's skill rank+ bonuses
10. Incantions (UA): Thanks to Aus Snow for reminding me
11. Complex Skill Checks (UA): Thanks to Aus Snow for reminding me
12. Weapon Groups (UA): Thanks to Aus Snow for reminding me
13. Fighter: To make them more interesting
a) use TOB: B09S all fighters to acquire some of the maneuvers as per the rules presented therein
b) use the Book of Iron Might (Malhavoc) if you don't like per encounter and don't mind taking a moment to build maneuvers on the fly. Just be sure to download the cheat sheat and additonal sample maneuvers from the website
14. Retraining (
DMG 2)
15. Monster/NPC design
a) Don't worry about accounting for every feat or skill point a monster/NPC has unless you are writing a published adventure or they are a cohort/ally. Just give them what think they need.; or
b) Use Wulf's system for Pathfinder that he posted her on ENWorld.
16. Swarm and Mob templates
17. Spells: to be added later