The actual map size end to end is already massive and way, waaaay bigger than anyone would ever need. Even a 10 man server...the current map size is fine.

What they really need to do is add more biomes and content in those biomes. Black Forest is basically just crypts and troll caves, Plains is basically just goblin village. Mountain is literally just silver veins...we need MORE STUFF to fill out what we have, not expand the map edges.