in bowser rolls, pokemon and fd were like 6 but fd was slightly smaller so we rounded it to 5.5. dreamland was 5, i think. yoshis and fod were like 3.5 and 4 or something. and i forget what battlefield was.
but yeah, stadium is bigger than dreamland in terms of length. overall, dreamland is the bigger stage, though, because of the ridiculously amazingly high platforms. this enables camping better than pokemon does (barring transformations).
to my understanding falcon's issue isn't peach camping turnip, it's when she gets one out to approach him and cuts off a bunch of his options with it. his other hassle, it seems, is approaching her directly, because his nair only beats her fast moves when it's spaced nicely and if he's making a move on her, she gets more time to position herself than vice versa.