Wanted to wait for the reaction from the Grey's Anatomy staff before I commented. Needless to say, there are quite displeased. Especially as they allegedly were accommodating of her burgeoning movie schedule this past season.
This could very well be a career destroying action for Katherine Heigl, since there is no reason for it. She could have simply not submitted and said 'no comment' or 'I was better last year' and she would have gotten props for being humble. Now, this will likely make writers scared to write for her. Imagine knowing that if you cast Heigl in your project, it'll be more than likely that you'll get trashed in the press sometime within the year.
The irony of course, and a telling sign of her apparent arrogance, is that the third season of Grey's Anatomy was criticized for being too Izzie-heavy. So, of course, now that this season (allegedly) returned the focus to Meredith Grey, Heigl complains and makes a public hissy fit. It's a supporting role on an ensemble show that's named after a different character, you can't always be the star.
If this is a public contract renegotiation (wouldn't be the first time), either for a raise or an attempt to be let out of her contract to make more movies, it's a very poor way to go about it.
This is at least the second time she's trashed the very people who write quality material just for her. If you recall, while promoting 27 Dresses last January, she criticized Knocked Up as sexist because the women (her and Leslie Mann) were emotional and, uh, three-dimensional, while Seth Rogan and Paul Rudd got to make dick and far jokes. Leslie Mann gets an Oscar-worthy role and gives an Oscar-worthy performance, but Heigl complains that the women weren't immature enough?
Men who truly seem to love women (Judd Apatow, Joss Whedon) are just as capable, if not more so it seems, of writing real, three-dimensional women, as their female counterparts. That's what was so annoying about Heigl's bashing of Knocked Up. She was lucky enough to star in the rare big studio film that gave us psychologically messy three-dimensional female leads, and she cries sexism because Rogan got to be goofy.
Being outspoken shouldn't be considered a positive all by itself. You have to be outspoken and... correct.