Quick non-gameplay complaint: The character naming system is kind of obtuse.
When you first sign in with your battle.net account, the game asks you for a character name. Once you enter that, it then asks for an identifier. The game says the identifier is required to tell you apart from other players with the same character name. However, the description seems to suggest that other players won't see the identifier and that it's mainly used for internal database purposes in order to differentiate players with the same character names. Unfortunately, anyone you add to your friends lists can see the entire name which appears as [character].[identifier]. I assumed it would only be visible to friends who were added via the RealID system. The entire name also appears as your handle next to all of your posts on the battle.net forums.
This is particularly lame since you can't change a character name or identifier once it's created nor can you delete/create a new character. Hopefully they'll let us change it in the future or at least wipe all the character/identifier names once the beta is over. I'm guessing with the final retail game, the [character].[identifier] names are going to be permanent unless you pay to change it as is the case with WoW.
You guys who get into the beta in the next waves should keep this in mind when you first log in.