I still feel that Nina...
Leaving the show was a disrespect to both the show and the fans. I posted something similar when it first happened which was quite controversial to say the least. Look I know we humans get bored doing the same thing over and over again. But I can strongly assume working on a successful tv show is something we all would love to be apart of. So i find it hard to see doing a show as TVD would be slave labor. Certainly beats a sh!tty mininum wage job at wal mart.
I think she should of just told Plec hey I will do one more season if its the last. That way we could get a proper final season with Elena and possibly Katherine. Now if were lucky Nina might come back for the series finale(and despite the rumors I don't think she will)and what will she do exactly? Wake up and marry Damon? Will she be killed off? I don't see how they are going to create a satisfying finale with one episode with Elena.
Now I know people will defend her saying its her life her choice I get it but personally I feel as the main lead of a show its good to see it through. Especially for the fans who made you the success that you are.