#1 - Sept. 8, 2011, 7:42 a.m.
This is obviously really problematic as RealID is persistent across Blizzard games and I don't particularly want, say, my private WoW alts to be visible to people with whom I'd like to play Diablo III. I thought WoW and Starcraft 2 struck a nice balance: RealID is there and available, but you can add non-realID friends if you want.
I'm really hoping that this will be the case in D3 as well, and it's just something that hasn't yet been implemented in the beta. If you have to use RealID to play with friends, that'll be a dealbreaker for a lot of people.