Not that I play anymore (sorry, two children under the age of two means daddy doesn't play anything without a 'pause' key) but here's a radical idea:
People's choice arena.
Every so often a poll goes up in the arena and folks respond with what arena type they want
Poll can go up either via UI pop-up or radio announce message ("Voting is open for the next 5 minutes, for night arena send "Vote 1" , for storm arena send "Vote 2")
Once polls close, arena switches to that "mode" for the next hour or so.
If you want the changes to happen more fluidly, set it up so that there's a "change / keep" vote first, but that happens more often (and silence = keep)
Choices for everything up to (but not including) plane sets could be set up. I say plane sets, just because folks may not relinquish their uber planes after the polls close
I should mention the two stage voting (change / keep) followed by "which setup" has been working great on counterstrike servers and the like for many years now.