I'm not at all surprised to see that more Grey's viewers are pissed off by the sudden return of Der/Mer than by the passing of Denny (Iz/Den?). But me, I like the way the show does Derek. I know people like that, really. I am a person like that. I like seeing his self-deception, how he believes that his ethics and reason can overrule his feelings, I like seeing how his anger at Addison is never really dealt with, I like the fact that nobody in this whole mess is a really admirable or totally worthless person. I can't quite imagine the show if he left Addison, she went back to NY, and he and Meredith settled down together. I don't really want that to happen.
What I'd like to see is some growth (rare, on-screen and in life), where he begins to catch on that his feelings about Meredith aren't really unrelated to his feelings about Addison's earlier betrayal. I'd like him to eventually catch on that what he needs to do is shut down the Mer business, come to an end of the Addison marriage, and go on to a new, uncontaminated relationship.
And that's what I'd like to see for Meredith, too, but I think it's less complex than Derek. I'd like to see her realize that the Derek thing is terminally messed up and that the vet is a real person, upfront with his baggage, with whom a future is a possibility.
And then I'd like Denny to come back to life...