Sorry about the double posts but I beat Diablo.
I didn't feel like sitting around so I fought him at level 27. My character did great all the way up to the final fight.
I'm glad I didn't underestimate Arctic blast because it was my main spell through out the whole game. I had no problem keeping my Dire wolves alive as long as I was freeze burning everything. Of course I would lose them now and then but that is why you have summon.
With Oak sage as an extra tank, three Dire wolves, three Ravens from a helm and Arctic blast, I walked through the whole game without any problems. I also kept Aliza from the beginning, she seemed to do good damage and stayed alive.
Fighting Diablo was another story, it seemed like I was the only one that could stay alive. Oak sage and the wolves would turn to dust the first spell Diablo cast. If it wasn't for Cyclone armor I wouldn't even of had a chance.
There was no special trick in killing him besides taking a real long time. All I needed was something to distract him while I would freeze burn. It was just me and three ravens for a while. I would resurrect Aliza now and then for an extra distraction.
I finally changed helms and used a level three Poison creeper instead of the birds. It was cool to see Diablo turn green and be annoyed by this thing. When he turned to kill it, I would lay in with a stream of Arctic blast. Other than that, it was just running around and throwing handfuls of blasts at him.
I guess I'll get to check out the new spells in Act 5
Edit:
One last change. <img src="/ubbthreads/images/graemlins/biggrin.gif" alt="" />
I finally got the Grizzly and really don't care for it that much. It just seems harder to control the mobs with one slow moving tank. I'll eat the point and start working on Dire wolf again. Not as much for the damage but more so to increase their health.