In the original first draft of this idea back last summer, I actually had it that you would draft your actors/director first...and then at the end of the draft there would be a random drawing to see what genre your movie was going to be in.

The idea being that it would throw a wrinkle into the drafting -- do you draft specialized personnel and hope for the right genre, or do you draft people who can work across genres and will be right for anything. Thought too it would lead to some very original/hilarious wrapups as the guy who drafted the entire cast of The Godfather found out that he actually had to do a romcom.
But changed my mind and thought people might get a little pissy about their vision, whatever it might be, suddenly evaporating at the end as the result of something random, and so drafting genres was born. Now if its going to be that incredibly onerous, we could dedicate the first round to nothing but genres so that people would have direction...but why be that restrictive? If you are worried about genre, take it first, but not sure why we would make everybody HAVE to take one first -- if somebody loves an actor just that much and wants to take them instead and is willing to risk the genre, seems to add something to leave that open as a possibility.
P.S. As an aside, I'm not sure how successful Rock Band has been as a format -- they have been the least viewed of all of these drafts aside from Cars (the most viewed was of course, Babes

). I think there are definite advantages to being able to see it all come together as the draft progresses rather than a big splot at the very end that may well be missed by anyone but the drafters. Its also of course the way the movie biz works -- get a script, get a star/director to sing on, then build from there.