I hope he stays retired.
I had hoped Jerry Rice would stay retired, but returning as a WR doesn't hold a patch to returning as a QB.
Brett should take a good look at Rice, Polk, etc., and decide to stay home, play golf, buy a few thousand acres in the Miss. Delta to build a hunting lodge, anything other than spoiling his legacy. Seems like his agent would be begging him to do the same. He can continue to earn from endorsements for decades if he doesn't go stink it up with the KC Chiefs or some such.
That said, if he does return, I'll be pulling for him. He's a great story and a super Mississippi boy no matter where he matriculated.