I'm found that so far using wall of fire, lightning (chain lightning thing) and gaseous blast on mobs, then righteous stomp to cast them back and regen my other spell timers to repeat.. seems to work great. on single or champion/higher monsters I usually stand close to them, use wall of fire to hit them more than once in a single use, and then blast away with ice bolt or fire bolt.

I see some people say mages are weak. I dont