I never played D1 or D2, and only for into D3 after the expansion. Did quite a lot of seasons and for me the game had a zen like quality when playing.

Blast through the rifts and grifts watching numbers go up. I could just almost play it trance like.

I enjoyed the colors and the feel of the game. I never got really into D4, but that has more to do with me having more obligations as a parent.

Edit: and DH Engineer with stationary pets should be explores as third WoW-DH class as a DPS/support class.