I think Burks should be getting 2-4 more minutes per game (from Jefferson), but agree that bringing him off the bench is ideal. His minutes are not so low that I think it's a problem (or affects his development). He's getting ample opportunity to initiate the offense off the bench and play late in 4th quarters both on- and off-ball.
Kanter's been playing more with Favors the last 8 games (this is partly due to matchups), and is finally looking comfortable and confident. His defense last night, I think, was very good. His good play has become consistent enough (albeit still over a fairly small sample) that I won't be surprised if Corbin starts increasing his minutes. I do think it's important that Kanter shows he can play well for a stretch of games (not just a handful of minutes or one or two games), doing the things the coaches ask, before his role and playing time are increased. I'm not convinced that good performance over a few minutes or a game or two are more predictive of future success than a stretch of games.