Chris Johnson's rookie play has been better than AB's rookie play. Who knows. I think if AB does not sign for reasonable cash then he is gone folks.
1) Chris Johnson is technically not a rookie. He played with Atlanta a little last year, but spent most of his time in the D-league, which isn't very dissimilar from AB's first year. If you consider this his second year, which it is, you'd probably take year 2 Bradley. I know I would.
2) Chris Johnson is 7 months older than Bradley right now. If you think that AB has no more room for growth in his game, then what you see with Johnson is what you get.
I'm not convinced that AB will be here next year, or even next month, but I think that we need to remember how young he still is, and how easy it is to get infatuated with a new shiny toy like Chris Johnson. Last year it was Shavlik Randolph and Terrance Williams, neither of whom are in the NBA this year.
I do think Johnson has a chance to stick around and be a useful backup. He's shown the ability to hit the 3, and he, so far, has given the type of energy that this team (and most teams) sometimes lacks. And at the minimum salary, that's useful. But at best he's a useful player that means you don't have to pay someone like Courtney Lee to play that role, and can save your cap dollars for a more impactful player. And while that's very useful (having players like Chandler Parsons and Patrick Beverley allowed the Rockets the room to sign Howard), he probably doesn't become a franchise cornerstone.