Mark is my favourite as a person this year (in a lovely bunch). I'd love to see him do a brilliant dance and get high scores. But really - no. As fatskia says, he looks to have issues with his fitness and particularly his knees that will limit how much he can learn in the time. He always seems to be walking very carefully when he finishes his dance and goes upstairs to Tess. He's better than many this year, imo, because I feel that he is dancing to the music, not just a set of steps he's learnt, and I don't feel the 'comedy' aspect has taken away from that (though that may change with M C Hammer). But I really get the feeling that Iveta is teaching him as much technique as he can handle with his knees, etc.
I also feel that maybe having the comedy content helps him have a bit more confidence.