I read pretty much all power of the barbarian last night. It mostly hard hitting power but often leave teh barbarian vulnarable, i really see now why they gave him so much hp, he lack armor and defence in general. He have to rely on Str and Con for main stats, leaving the other 4 stats low and that give low defence in other field then fortitude. His a lot like the 3.x barb alot of HP low AC and save, take all the hit but have alot of hp to soak it up.
Sure you can hit quite hard but mostly one combat per day early on, later when you get more daily power and can fly into a bloody rage more often but still you have to blow your daily to be really effective.
Ranger was one of the best multi target striker but the barbarians seem to focus on this too, rogue i think is still a better single target striker more side effect and sneak attack is just awesome. Warlock are the best range striker they hit from affar and their curse, bow ranger cant match a warlock but come close to it.
So barbarian look like a mix of a ranger for the number of targets and the rogue for the damage it deal.
It look very fun to play i will try to make one for a game o play test it but i am not sure i can do it soon.