I really like this idea, honestly if it were implemented, the first thing I'd try to get a hold of is the music celebration background. XD During the event I got all the traits but that one. I spent another 5 hours after I had gotten everything else just trying to get it.
However, some people could make an alt account, buy traits they want on their main, donate them, then pick them up on their main. Therefore not spending any of their precious gold they need for events and exclusive sets on store stuff. I think that would be a major issue.