I will definitely miss Cristina because she did bring the drama, but after her and Owen broke up it was pretty much the end of the line with what Shonda Rimes (the show's creator) could do with her. I just want to know how she is going to exit the show. Shonda does have a history of killing off her characters...or making them break up with their significant other (which, as you can see, has already happened).
Dr. Burke - left Cristina at the alter at the end of season 3
Dr. George O'Malley - gets hit by a bus and dies on the way to tell his mom he joined the army at the end of season 5
Dr. Izzie Stephens - gets fired and leaves Seattle and Alex, who she was married to at the end of season 6
Dr. Richard Webber - (SPOILER) Richard supposedly dies at the end of season 9 during the blackout
Dr. Mark Sloan - dies at the beginning of season 9 from injuries suffered in the plane crash
Dr. Lexi Grey - dies at the end of season 8 after the plane crash
Dr. Charles Adamson - one of the transfers from Mercy West, killed by the shooter in the season 6 finale
Dr. Reed Adamson - one of the transfers from Mercy West, killed by the shooter in season 6 finale
Adele Webber - gets Alzheimer's and then dies in season 9 of a heart attack while living in a home
Other Break Ups
Dr. Addison - leaves Seattle at the end of season 3 because she wants to date Alex and he isn't down...then she decides she wants a baby and moves to her spin-off show Private Practice
Dr. Erica Hahn - dates Callie and then they break up...and then she leaves
Dr. Teddy Altman - gets rejected by Owen as a lover then as a friend...and then she leaves
Of the original season one cast only Patrick Dempsey (Derek), Ellen Pompeo (Meredith), Chandra Wilson (Bailey) and Justin Chambers (Alex).
Other cast members still around are Jesse Williams (Jackson), Kevin McKidd (Hunt), Sarah Drew (Kepner), Jessica Capshaw (Arizona) and Sara Ramirez (Callie).
The originals along with Sandra signed two year contracts at the end of season 8 and could also potentially leave at the end of season 10 along with Sandra. MASS EXODUS. Just kidding, but don't write it off.