I would love a pay per game system so I could just pay for the Bills game when they aren't on regular TV (not very often here). However, everything they've come out with to watch games has been a buy everything model. I'd be surprised if that changes. No way NFL is going to do anything to make it cheaper for you.
If anything it'll be like NFL Ticket, only stream it instead. Not sure how that jives with DTV's exclusivity arrangement.