What I get alot, is that for example Erebus - Bite doesn't work. The char just doesnt move. Usually takes 2-3 tries until it works again. This happens with other spells too, I have heard.

With Regulus (other DGs too I guess) another thing that is annoying is the fact the when you chase an enemy DG (got a lock on him) and you cast for example Wand of Speed, the lock goes a way and you just stand there. This is really really bad. An attack lock should stay until you release it with another command, or you get stunned/interupted (maybe even then it should reapplay once the stun is over). This would make thing a hell of alot easier.