The problem with new Who is Russell T Davies really can't write science fiction. He is great with characters but the plots always fail at the end with a big shitty deus ex machina.
The third series was fairly average until the second two parter, then it was great until the finale. It was only the episodes that broke the new formula that worked, longer stories, hardly any doctor in one episode!I'd love them to do a Christmas special old style, 4 half hour episodes with time for the story to develop and flow, and a lot less running down corridors with the camera at a funny angle!