Armor Lock isn't overpowered. You just suck at Reach :)
Reach isn't bad, you're just a BK :)
For my gamertag, look up "Ghoulishtie"
Halo 3 had a BETA. (Bungie implied it, so they could get data about how online play would work for Halo 3's full release)
Halo 3: ODST is just a new campain and a new co-op mode. Why would it need a beta, or demo? It comes out within the next few months, and it doesnt have much to do with multiplayer. (besides firefight)
Halo: Reach however, is told to be pretty different than what we know from Halo 3, so it's multiplayer will have a Beta under 'extras' in each copy of ODST. The beta however, will not be open until sometime after 2010.