ZoiDUX I think this would normalize name changing more and would make things a mess.
Example: Jerry likes to go by TenaciousGirth on Tuesdays-Thursdays, FlamboyantFlamingo on friday - sunday, and SillyClownFish on Mondays. Now multiply this person Jerry by at least 30 and that's everyone's friends list that you have to track, each and every single individual person.
Chaos, I say.