Due to finding my motivation to write again, I will definitely be joining this contest, so here's some feedback I guess.
I might be able to write a worthwhile game in a month, but I'm also a terrible procrastinator (sure I'm not the only one on the site) so the two month model would definitely be the way to go imho.
Themes? I liked the whole pick-a-prompt theme for the last contest, and the post-apocalyptic contest from about three or so years back was pretty cool. But, we already did those, and honestly I think all the bases and genres have been covered with the contests. I think it would be cool to see a contest with traditional CYOAs as the theme, that is no scripting, no variables, etc. Just a branching story dependent upon your choices.
Awards? Really, I don't think there's anything for awards that hasn't already been offered, IE points, trophies, featured games, etc.
So yeah, there's my two cents.