It seems like the map rotation gets pretty static and repeats pretty quickly. Market Garden, Kursk, Liberation of Caen and Battle of the Bulge seem to be in heavy rotation and I see they sync up with Simple servers sometimes.
Market and Liberation are almost always in the rotation, yes. But you're mistaken on Kursk and Bulge, though. We do not look at what other server have in their rotation just so you know.
Does Moongamers just use the default retail maps or are there any plans to introduce something new?
Like many server we only run the 'stock' maps on our main server. We do run all the expansion packs every sundays. The stock maps we run are serverside modded by us. We are also working on some of the maps. What do you mean with something new? New in player made maps?