Whenever he's ready to pass along the baton, I think the guy who is ready to pick it up (although I don't know that he wants the gig) is Ta-Nehisi Coates. Here he is on Obama and impatient liberals (but do click through and read the full post):
I keep meeting lefties who tell me Obama's "too soft" with these guys, and I keep looking at them like they're crazy. I am going to go out on a limb and say that there is something deeper at work here, something beyond the policy fights. I think a lot of us don't just want Obama to be effective, we want him to exact some measure of revenge. It's smart to understand the difference between the two, and moreover, how the desire for one can undermine the other. A section of conservatives love Sarah Palin because she drives liberals crazy. That she drives a lot of other people crazy too, and hence undermines herself, is beside the point.
Let's not make that mistake. Besides. If it's blood on the walls you want, the GOP is doing fine by itself.