I think the signing was more of an "Atlanta Hawks" move to get people playing for them. True they have cp3, david west, but after those two theres nothing more. If you add a third player over there like peja, players who may not want to play there may suddendly change their mind. The team would project an image that it was willing to win and is going to do what it takes.
Off topic but I am really disappointed with the JR Smith situation