I agree with the name searching, however it would be challenging if some idiot tried to add someone with a YouTuber name like Sky, or KennyBE, or even calobi44. Perhaps if the system were more like XFire's friend system (it's an in-game client for PC), where users had a profile name, and then a user name. Then it would omit the profile name search results, and give you the username results instead. Since you can't copy usernames, it would make "friend-ing" people that much easier.
I agree though, the FB thing is too overused these days in games. Whatever happened to inviting users via email!?