Sorry if this is the wrong board, the only other place I saw for suggestions was a champ concepts board.
I was wondering, how difficult do you imagine it'd be to make a map editor program? Separate from the regular game servers, of course, but you'd be able to make and test out custom maps other players have made, and then have sort of a voting system.
High voted maps would make "map of the month", or something like that. You wouldn't be able to do ranked matches in em, because the maps would be new to everyone, but you could still do stuff like normals and player vs AI matches.
The map editor itself would be relatively easy to use, just drawing out paths with the line tool, adding ground textures, and planting creeps like a custom Warcraft map. You could allow/ban different weapons, bring in bosses from other maps, and even (with proper coding skills) include new models or creeps.
Whaddya think? MIght be a bit out there, but I think it'd be a good idea to toy around with.