Ok, what about this as an approach,
Three types of competition..
1, The slow burner, no fixed deadline, no rules as such, just a basic theme. (like DB's requiem challenge)
2, The quarterly competition, more rigid rules, often to run with mixed up pairings to help the community to flourish.
3, The quickie competition, maybe one or two weeks duration, for those of us who write and record quickly. (current affairs songs etc)
People can pick and choose what they play, and when. It will allow for the less structured 'challenges' as well as the more last minute, topical competitions (like if something inspires us in the news)
What do ya reckon?