I actually chose them because I figured they weren't too bad, but as we played the flaws in them got exposed to me very quickly, and I knew things were really fucked up when, on the transformation stages, we spent half the match camping each other.
Call me naive for sure, but now I'm heavily reconsidering supporting them all. I just don't think stages with transformations work well with the kind of meta Sm4sh has, encouraging defensive play massively over offensive play and overemphasizing using the stage to your advantage over your character's strengths.
The Lylat tilting shit is especially bad because I don't think that was in Brawl, so no doubt the dev team fucked up on that one.
I complain about them because, well, it didn't seem right to me that I could get the win through taking advantage of the stage despite me doing exactly that. I know, I'm being hypocritical, but I think my message is valid all the same.
Also, now that I think about it I don't recall seeing you use custom moves with Bowser. Are they really not good options?