The show is completely dependent on how endearing each actor can make the Doctor.

Which is why Colin Baker only lasted one season. The writers wanted the Doctor to be more terse, more like the first through the third, and the fans didn't like it; or him, since he was a good actor who was limited by what the writers, producers and directors wanted him to do.

While I am disappointed by the casting, I want to see the writers, directors and producers step up and give him excellent content to work with, like they often did for Chris and David. I am hopeful for an older companion though, because I want my asexual Doctor back plskthnx.

/complaining. ;-)