I read somewhere the developers said it was game breaking. Too much of an advantage. Personally I don't think they had enough time to balance the **** out. Would have been a great feature, that's for sure. Wish more games would make use of our tablets and phones as a second screen.
Although it would be nice, I don't think it's needed. I'd rather just do everything in game. It's more of a gamers preference on if they would want it or not though.