Gears 3 is fall so possible. Played the beta, it's terrible. Another Gears 2 with different maps....boring!
You played the MP beta so I doubt thats going to be the finish product. And thats just MP maps so who cares. I rather they focus 100% on the solo and screw MP. Then again, I say that for all games. Anyway, I'm betting Gears 3 has the new disc format unless they run into issues.