Here is my opinion on the subject :
Early, I think mages are a bit weak --> few spells, low damages against crazy magic shields, etc
So I built a duo lone wolves team of 2 summoners.
Incarnate champions carry you during the first Act.
Then Act 2 you get much stronger spell (source spells btw), and you start blasting things.
Take critical chance, scoundel, and start making hell rain on the lands below you (just get the high ground you fools).
Then just grab Apotheosis and... you know the rest.
