Well, the stage is kinda small, so you don't get a lot of breathing room in the MU, and it's rather easy for ether character to feel cornered, which is good and bad. You really have no where to go when Marth starts throwing you around so if you mess up the fthrow/fsmash Di trap ER w/e you wanna call it, you can die before 50 or something gay like that. The boundaries are sorta small but the stage itself isn't to small, so a raw tipper from Marth or a spaced fsmash from Mario won't spell certain doom from any random place on the stage. Usually you can get a fat edge guard or at least stage control from a solid hit though. The moving platform doesn't seem to be that great for ether character and IMO it isn't that useful. The walls are a plus, but I feel like this stage is better for Marth than it is Mario in this MU.
Idk if there is a stage that could off set the MU some. Maybe if there was a medium sized stage, with a wall to wall jump and platforms that were out of Marth's tipper range. Like maybe, castlesky, but with walls! Except, make the boundaries smaller
^