It was viewed as massively lopsided. From Forbes:
The ACC has signed a new multi-billion dollar TV deal with ESPN, but could it have gotten more? Maybe.
www.forbes.com
"Whatever the case may be, the ACC is certainly hoping that its new deal is enough. If not, the conference may go the way of the Big East as it helplessly watches its teams go running for the hills."
I'm sure there were some people who felt the positives outweighed the negative, just like there are people who see the positives in the Big12 deal. There might be more to the Big12 deal, but from the outside looking in, getting the naming rights for an entire conference should be valued at a lot more than a couple million per team (and i think it's actually less than that).