Someone mentioned this problem earlier, but since we got one game mode more, which gives us a total of 4 modes*, I think 3 map choices is not enough. The most straight-forward idea would be to add 4th slot as an experiment, but since we have at least another one mode coming some time (skyball) there may be a bigger push to some more substantial solution.
Perhaps we could vote on the mode first and only then on the map on this mode? Or depending of the mode vote system would choose different number of that mode (i.e. 2 maps of the most popular mode and 1 map of the second most popular? or change it any way you please if we talk about 4 maps: 3-1, 2-2?)
Edit: When I think of it we can't have result of mode vote be 3-1 most popular and second most popular since... there are modes that don't have 3 maps. That's awkward.
*deathmatch, king of the hill, crazy king, VIP