There's only one thing that itches me a bit about this MAC, that being the decision to only allow new submissions to enter the contest. I'm personally not effected by this, since I don't have any submissions that would fit the theme, but I believe that will leave out some submissions that could otherwise get a high ranking.
I understand that the previous discussion about MAC8 lead to this, due to the fact that a monthly contest should only include songs made within that month (and because the only logical premise for a song to compete would usually be that it was made FOR this MAC), however there are a few situations that make this a bit complicated. For example, just a few weeks before the last MAC began, I wrote a song for a user that ordered it to accompany his flash movie which centered on a very tragic, depressive event. To me, it was probably the best song (I could make) to depict that theme. Soon, the MAC came along- and hey! That submission fitted the idea perfectly (in my eyes, anyway).
My point is: someone could have made the PERFECT song to this theme already, but not be allowed to enter the contest with it, simply because it was submitted before (and YES, I know there was talk about a pre-MAC period in which the songs should fit if they wanted to be excepted anyways).