Got to play a little Temper yesterday and I had a few comments.
1) He's a lot of fun. Definitely the best iteration of the character thus far.
2) I feel like his MB2 ranged attack's cooldown is too long. Considering it costs rage and the rage decays, I feel like he should be able to use it more when he has the resources to do so.
3) I dislike how his passive eats his entire rage meter. It seems like something you want to avoid, and when you don't it's not powerful enough.
4) He can't use 1/3 of the in game drops... (mana drops) and they are the most common one
5) Bringing gear on his is almost a waste of time. Most gear you want to trigger BEFORE you engage the mobs. Mana related gear is totally worthless and stuff like Gnomish repair kit is hamstringed due to the nature of having to autoattack to gain even the smallest amount of rage. All this adds up to you having to sacrifice potential combos in order to manage your rage.
6) Unchaining should provide unlimited Rage IMO.