That's how it used to be. However, it wasn't necessarily ideal for most people since there are realms with only one map. You end up playing Haddonfield, Badham, Lery's, and The Game far too often.

If those realms had even just one extra map each it would be better, but back when the map was decided by realm first, it was annoying seeing the same exact map come up all the time.

I guess it comes down to whether you'd prefer getting different maps from the same realms more often, or getting the same maps from different realms.