And, yet, I fail to see where this "levels the competition" between casters and non-casters. First, as you just stated, this don't makes him good as your T1 and T2 classes EVEN with the planned nerfs to them. Second, it creates several boobytraps: The aforementioned Raging Specialist Barbarian is inferior in every way to the Raging Combatant Barbarian, and the Raging Combatant is inferior in defense to the Invulnerable Rampaging Specialist Barbarian (the rampaging barbarian got better defense with the DR 32/- AND gains fast healing 10 and 20 temp HP per round vs DR 5/-) AND inferior in damage (as the combatant does 8d6+48 (mean 76 damage) in one target with a full attack and the specialist does 19d6 -mean 66,5 damage- in the first round, then 19d6+4 - mean 70,5 damage - in the following rounds while also dishing debuffs AND buffs simultaneously to a 180ft range). Sure, the enemies may save and take half damage, but so the attacks of the combatant may miss...

Again, as another point, I fail to see why take Mighty Swing and Mighty Swing, Greater. If you're a Combatant, the increased damage will be lower than your standard full-attack damage (it gets worse with the rage and the frenzy, even with the frenzied rider on Mighty Swing since the enemy can save for half damage or even 0 damage with the right skills), and if you're a Specialist, it is inferior in every way to Battle Roar (less area of effect, damages companions, no buffs, no debuffs).

In my humble opinion, every decision should carry pros and cons or it is not a decision. There are very good points in the class design: the decision between frenzy or rage is a good example (as rage got good offense and defense while frenzy got superb offense and little defense), but if an option is clearly superior to another in every (or almost every) aspect, there is no decision to make, as it becomes a test of "system mastery" separating the "n3wbs" from the "pr0s". And I'm surely only scratching the surface here: I'm by no means close to a pun-pun level optimizer.

Please take this words not as a personal attack or a deterrent to your planned actions, but be prepared for the need of lots and lots of playtest, as the sheer number of moving pieces required to craft the charaters makes the possibility of creating exploitable system holes and vastly underpowered characters will be huge.

PS: I'll know I'll generate a lot of hate with this confession, but I did like D&D 4th edition. It had it's flaws, of course, but one of the points that were great in it was: It was freaking HARD to create a weak character. I mean, there were stronger and weaker character options, but even if you chose the weaker options you could still be doing the character's intended role (striker, defender, controler or leader) well.