Tech-Adept has several additional unique passive skill tree. the Power of the Tech-Adept is focused in his robots. Tech-Adept acts as a means of coordination and support. i dont feel disbalance. someone even consider him too strong.

There are some very powerful builds out there when you play like that.

I find that going in solo combat with the adept is really not the way he is intended to be played as the adept himself is not strong in solo combat. Ranged or melee should be used when appropriate and probably only in support of the minions.

As far as the skills are concerned for adepts: Adepts have several unique passive skill trees that are centered around boosting the defence, attack en versatility/abilities of your minions.

I have to admit though that as far as ranged combat is concerned, the weapons are my leas favorite of all ranged weapons out there. Maybe because the damage output is low, but I feel that even in support of the minions it doesn't contribute to the battle.
So I play him with minions, sit back, keep him out of harms way and watch the minions do all the work. It's a pretty fun way to play in my humble opinion.