The AoE aggro attacks is a great idea -- give the tankers the ability to do what they do (hold aggro!) easier...
And I love the general concept of "tanker rage" --
But I do share the previously mentioned concerns about basing the damage buff on the number of hits landed.
This encourages tankers to haste/recharge reduce their attacks, and favor quick, weak attacks over the pounding whollups that "fit" the tanker more.
An alternate proposal:
Instead of number of hits he lands, how about basing the rate that the Tanker *Rage Damage Bonus* increases on the number of enemies in near proximity that the tanker has aggroed.
So imagine the *Tanker Rage* meter (the higher it is, the more damage a tanker does) -- as a thermometer that "heats up" faster the more enemies in close proximity the tanker has aggroed (feeding off of their aggression I guess?)-- This rage-o-meter could get drained significantly with every melee attack (essentially, the Tanker Rage aggression is released into the attack in the form of extra damage -- think of it as the tanker blowing off steam-- higher the meter when the attack is released, the more bonus damage). Of course, the meter would also drain when there aren't enough aggroed guys in close proximity-- and you might have take in account the difficulty of the opponent to prevent farming "weakling" enemies just to build up and release attacks on bigger opponents. Definately a system that would have to be tweaked to encourage the desired tanker feel.
This system would reward tankers for doing what they do. The more guys they draw in and aggro, the faster their rage-o-meter builds up, and thus the more often they could release more powerful attacks (the rage-o-meter would "max out" at some point [great opportunity for a cool visual tanker rage effect]). Since the rage-o-meter is drained with each attack, it also rewards attacking less often and going for the "big blows", which really fits the tanker feel.
That's my suggestion, take it for what you will
