I played with a 5D MIII and a Canon 24-70mm, one of the best camera setups I have used (I swear the camera out of focus was as sharp as my little old D5200 in focus ). It didn't take me long to start looking at the Tamron 24-70mm, my question is would this lens be wasted on a cropped sensor?
I think only you can decide whether 35-112mm is a focal range you are going to find useful or not.