I'll admit, Season 9 hasn't done anything to make me watch it. At all. I watched the first two shows, then just forgot about it, only remembering it was on when E4/C4 advertised it.
To me, it's just lost the ability to balance comedy and drama as well as the previous seasons did. For example, Ben Sullivan's plot and his battle against Leukaemia is a prime example of the way they used to balance comedy and drama perfectly, making fun of a rather sensitive subject whilst addressing the seriousness of the subject. And I'll echo the comment of standokan and Pariah87 on this page, without the Janitor, and of course JD, it just seems like they've said "Right, we know this will be poor, lets just roll it out, wrap the show up and move on." Plus, it appears to me Dr. Cox is no longer the Cox I know and love, he seems to be just a jackass. Which, admittedly, he was but he was a jackass that cared and had some great one liners/rants. This time out he just seems to be pure anger.
For me, it should've ended when season 8 ended. The last episode of that season sort of wrapped everything up by showing a few glimpses of what was going to happen with the lives of others and JD. That should've been the time they bowed out and walked away. Season 9 just feels like an attempt to try and regain lost glories.
...
It also doesn't help that the new cast are extremely unlikeable. >>