To be honest, swamp is one of most balanced and interesting zones (no, Miyazaki, i have no love for poisonous swamps!). It looks quiet and dangerous in same time - and it is! This is scary place - just as it has to be. Cant say so about Mountains since it looks empty at this moment. And the Plains is a bit boring, too. BUT! No swamps at shore please... it makes no sence. It must be placed at the river's end or so.