I think Ainge did a good job drafting Kelly. Let the kid grow, he'll be useful either as a trade piece or a 6th man point center. His scoring has been terrible so far, but he knows where to be on the court, and he's really good setting his teammates up. He's going to be a good offensive player.
His defense is something I'm not so sure of. He's a smart player, and should pick up team defense, but his one on one skills are not so great.
I'm not the biggest Kevin Love fan, but if Kelly and Sully work on his game and bodies as hard as Love has done, they'll be a lot better. If they think they're good as is, their careers won't be too brilliant.