Dang, that's a lot of replies o_O I should consider advertising on my title more often. :
Anyways, thank you all for the feedback guys, you have no idea how cool it is to me to receive some.
Wuthering: I see what you mean. SMW's overworld graphics definitely weren't made for clouds; on the other hand though, using new graphics in one single submap (especially a "regular world" one) would be kind of a big impact imo. I prefer to try to get around my issues with this map without having to draw brand new stuff, at least.
I agree the decorations are kind of nonsense in a cloudy surface, but I'll consider removing them as a last resort since the cloud would look even more flat/bland without them...
CxGx/will: definitely a good suggestion. This is what I should've gone for from the beginning... I'm kinda unmotivated to do any major changes right now (splitting the clouds would require me to move paths and events around), but I should do it sometime if I find the motivation and inspiration. Thanks!
Magi: totally agree with you. The only reason I didn't do that at first was that if I changed the cloud's outlines, it would affect the outlines of the wall intersections as well...
Which uh, could be gotten around with a single tile recoloring.
Hopefully it looks more cloud-y now. Also again, I might consider the other suggestions in the future. And thanks again!