High ceilings are good because she's floaty, but usually doesn't kill off the top. Wide blast zones can be good since she's got a strong recovery and good gimp potential. Small stages limit her ability to pull turnips somewhat. Large stages may convey marginal benefits over medium ones, but only if the opponent can't capitalize on the additional space. Platforms can be useful, especially lower ones that are at a good height for utilt pokes. That said I'm not a huge fan of Lylat as Peach, I feel like that many low platforms ends up just getting in the way and her platform game isn't really that good.
Most of the time I just pick a medium-size stage that I feel doesn't cater too strongly to whatever my opponent's good at. Sometimes I'll pick Skyloft for mindgames; a lot of people aren't comfortable on that stage. I usually go Link if I'm planning to pick Skyloft though.
EDIT: Walls below the stage are cool since you can booty bomber off them. Not a huge thing, but it's there.
So that in mind, would you say something like (and this is basic, fyi):
Pros: Battlefield, Green Greens, Yoshi's Island, Norfair, PS2, FD, and Skyloft
Counterpick: Yoshi's Story, Fountain of Dreams, Lylat, GHZ, and Smashville?
based on similar guidelines to what you said, at least. I feel at least the first 3x of each is right, the rest were kinda discussed with a friend and not sure still.
