I think True20 might be what you're looking for.
Kashell said:
XP system - Arbitrary and needlessly complex. The DM should assign XP as he or she feels, not as the rules dictate. (In more rules-lawyer environments, such as Living Grayhawk, XP values are already planned in game write-ups so why have such a complex system??).
In True20, you level up when your GM decides you should. No XP.
Hit Points - Soldiers and adventurers in real life stop fighting after they're wounded --not after they keel over and die. It makes no sense that a fighter should have 300 HP and only feel hurt after getting down to zero.
In True20, you have a Toughness save instead of hit points, and failing a save by enough means you're shaken (-2 to attack and skill rolls) until you are healed. A high-level fighter still has to watch out if he's surrounded by a mob of low-levels.
Hit Dice - Just because I'm a Barbarian, and you're a wizard, I have three times the amount of life as you. What?
In True20, Toughness save is Con+armor. If the wizard has a good Con, he'll be about on par.
AC - I'm wearing a ton of armor, therefore you can't hit me.
In True20, armor only adds to your Toughness save, that is, how well you resist being injured. It has no bearing on how hard you are to hit.
Initiative - I'm more flexible / faster than you, therefore I'm always the first one to react in situations. (It would make more sense if initiative was based on wisdom -- skills like listen and spot.)
Alright, you got me.

True uses Dex as well, though I think I'm going to switch to Wis now, to give it something other than Will saves.
Strength Adds to HIT - I'm strong, therefore I aim well.
Dexterity Adds to HIT only if I take a special feat (or ranged) - I've got good hand eye coordination, but I don't have this ability, so I can't aim melee attacks.
In True20, Dex affects all attack rolls. Strength affects damage with melee weapons.
Platinum Pieces - Where in the heck did medevil soceities learn how to smelt platinum?!
I got nothing. Well, except for the fact that True20 uses an abstracted Wealth system rather than individual gold piece accouting.
Two Weapon Fighting - Historically speaking, two weapon fighting was another method of defense, just like using a shield. It was also employed as a method of disarming opponents and confusing enemies. But never was it used as blatantly attacking an opponent like one would do with two fists. Drittz did it, therefore I can too.
Two weapon fighting has always been about emulating a swashbuckling feel, not realism. True20's TWF is much the same as D&D3.5's, except you can always move and attack with your two weapons.
Bard - What the heck were they thinking?
Druid - nature boys are suddenly religious too?
Wizard/Sorcerer - FAFS (Familiers are free stats)
True20 doesn't have specific classes, just roles: Warrior, Expert, Adept. Pick the role you want, and all class abilities are feats. Completely customizable.
Listen and Spot - Why isn't this one "sense" skill?
Climb, Run, Swim, Jump, etc - Why isn't this one "athletics" skill?
Move Silently, Hide - Why aren't these a "stealth" skill?
Tumble, balance, etc - Why aren't these an "acrobatics" skill?
I believe all of these changes exist in True20. Except your "sense" is called "Notice".
Full Plate - -6 Armor check penalty? And Full Plate is one size fits all? +1 max dex bonus? Last time I checked, all full plate must be custom made to fit a specific body type, and because the plates work so well together, people can do acrobatics while in full plate.
Even in D&D, fullplate has to be custom-made for the individual. True20's fullplate is similar, except that you don't lose any movement.
Shields - Wow, if I didn't know better, shields are worthless. Wonder why the Romans sent full armies into battle with full tower shields and did just fine with little or no armor?
In True20, shields add directly to your defense. Having a shield is one of the few ways to significantly increase your AC.
Attacks of Opportunity - My enemy is suddenly able to attack (again) because I did something.
True20 doesn't have AoOs. If you want to hit someone because they do something, ready an action.
Multiple attacks - I move, therefore I attack only once per round.
True20 characters only have one attack a round, unless they're using TWF.
Multiple attackers - two hundred bears attempt to jump on an adventurer. None of them are able to hit him, because his AC is obviously, too high.
True20 does feature an AC system that rises slightly as the PCs increase in level. But because Toughness saves don't really scale, two hundred bears is a serious problem.
I know I didn't address everything, but it really seems like you'd be better served by the True20 rules set.