I don't think you should remove the Rage entirely, since it's really what sets the Barbarian apart from the rest. IMC, we reworked the Rage ability into something you might like. Basically, our thought was that the classic "Rage" ability, the defensive stance of the Dwarven Defender, the trances of some splatbook PrCs, etc., were all part of the same thing: tapping into some primal force in a physical way.
The way we do it is the player builds his Trance ability by mixing and matching.
> Pick a Major Drawback from a table. These include the Barbarian-style "can't cast spells/concentrate", "can't move" (DD), "can't control trance entry", and more.
> Pick three Minor Drawbacks. These include:
-2 to (one physical stat / one save / AC / attack rolls)
1/2 movement
Fatigued after trance expires
Can't voluntarily end trance
Takes a Full-Round Action to enter trance
(and you can't pick a drawback that overlaps with your Major Drawback)
> Pick 3 Bonuses. At level one, these are all +2 to (one physical stat / one save / attack rolls / melee damage). You can pick the same one multiple times if you want.
At every odd level, add another Bonus or remove one Minor Drawback. At higher levels, more unusual Bonuses unlock, like Damage Reduction, mental stats, AC bonuses, faster movement, weapon Flurry, Evasion, longer duration, and so on. If you just put all of the bonuses into STR, CON, and Will, and removed the Fatigue drawback, you'd pretty much have the PHB Barbarian.
Basically, this allowed us to keep the Barbarian class without having it always end up as the "Hulk SMASH!" type of mentality. One player played a Barbarian/Rogue multiclass with a trance that pumped up DEX and damage reduction, and it worked really well.
