Lag bothers me as a potential issue, but AI confusion is really what bothers me if they ever add this in. 3 on 3 may be OK, but if it's 6 on 6, I can just see people moving defenders to form a conga line on one side of the line to confuse the OL. Maybe it wouldn't be an issue with Real Assignment AI, but I imagine even the greatest CPU logic ever programmed would have a tough time handling some of the cheese it would get thrown at it with the more human players on the other side trying to break it.

Now, with the right group of guys, football OTP could be a lot of fun. It's just when you throw in randoms that I have serious questions. Maybe you can limit pre-snap movement to help counter any issues.