That seems pretty weak to me.

I like the idea very much, good job ! I wished wisps move around and heal nearby allies. I don't really like the talents though. I think they are complicated and there is no talent improving wisps. It could decrease cooldown from 5 sec to 4 sec, increase their life point by 100%. Why ?! I think it should be either +75 armor from non heroic or +25 armor (from everything). And he seems like a support to me, not a specialist. Specialist shouldn't have basic abilities to heal allies.

At first I thought "nice", but... I think this hero is too similar to Jaina and Arthas, and he doesn't bring new mechanics. Another problem I see as a player : the numbers feel wrong. Specially the frost armor 2,5 seconds of 20 armor ?! This is crazy bad. So you spend 65 mana to decrease 2,5 seconds of basic attacks ? (2,5secs of AA = 0-500, 20% is 0-100). Imagine now if you choose Ice Lance : you become a "One button Hero". I would imagine this Hero being a Specialist if...