Things I would change...
Gosh, there is a lot I would change if I could, so here goes...
Often it has been mentioned that as characters gain levels it is to simulate that they are better and weaving and ducking in the midst of battle, thereby simulating that it is easier for them to evade and hit better in battle. The easier to hit part is summed up by an increasing BaB bonus, which I understand. But to say that Hit Points sums up their ability to get out of the way of an incoming attack is just wrong. Why doesn't the BaB, in some way, also dictate how well they are on the defensive in combat?
In other words, incorporate a Defensive mechanic similar to Wheel of Time and Star Wars and get rid of Armor Class, and have armor do Damage Reduction as in Star Wars. Also, you would get a more cinematic feel to your combats this way.
2. Modify hit points so either you don't get as many, or make it like VP/WP...only the WP hits truly count, and if you get hit by a critical, you GET HIT by a critical. How many times have you rolled a critical hit and you rolled LESS damage than a normal attack??
3. Modify the skill points system so all Perform skills are split up, like Craft and Profession.
4. Give the Bards 8 + INT skill points per level and lower the Rogues to 6. If the Bards are the jack of all trades, why do they get only 4 + INT per level? Why do rogues get more?
5. Give all 2 + INT sp/lvl classes 4 per level instead, and make general Knowledge skills a class skill. Leave arcana for the spellcaster types.
6. Some races should automatically provide certain skills as class skills, regardless of class, or make it an option. Any skill that they get a bonus in should also be a class skill for that race. Allow humans to pick any two skills as class skills for that race. Craft and Profession are class skills for everyone, regardless of class.
7. Keep Attacks of Opportunity, but also include line of sight and attacks from behind. To simulate that there is no 'facing' is ridiculous. If you attack someone from behind, you are attacking them from behind, right?
8. Completely and utterly redo the magic system. You might disagree with me on this, but I call it Fire and Forget, and I personally think that the entire concept of it, and how it works, to completely stink. This, more than anything else, though is my personal bias. I use the system as is because everyone here likes it, and I do have fun with it, but it could be SO MUCH better.
9. Less emphasis on magic items to increase the power of the characters. Allow for magic items to increase in power with the characters.
10. Rate of Fire for ranged weapons would also be a good thing to come back.
11. Incorporate hardness rules and armor points for structural integrity for armor worn. If the armor gets hit, wouldn't it get weaker the more you wear it? If not, what's the use in spending points in armorsmith skills? same for weapons?