Chase has gotten considerably more interesting and more nuanced. I don't think Foreman or (especially) Cameron have at all.

This. I think I said it farther up, but there was talk of who's "ready" and who's not, and though Foreman is the one who tried to leave, I think it's really Chase who's ready to do this on his own. He can pick apart House in an instant, and unlike Cameron he doesn't judge, merely observes.

They spent all these episodes on Foreman leaving, and all angsty about him going, and I was thinking, "You're going? Good. Have you left yet? No? Why not? I don't care about your angst, get out of House's office."