I never liked the redesign they made on her dress - those things on her hips and making it more poofy. I Melee, her dress was tighter and didn't look like an inflated balloon as soon as she moved.
Also, her dress flew up a lot easier in Melee than in Brawl (Icicle Mountain, heh heh). They also made her face more doll-like compared to the more mischievious face she had in Melee.
Plus, they changed her facial expression when she landed from a missed Peach Bomber. In Melee, she looked "ouch, that hurt!", but in Brawl she merely closed her eyes. Did she put on weight or something and had more cushion for the landing in Brawl? LOL.
One big improvement for Brawl, though. Her panties got a cute lace design with little peaches on the edges. <3 And yes, of course they put work into such detail because they KNEW people would look. I hope they have a similar surprise in this game, maybe making the panties a little skimpier and show soem butt cheek? NamBan is programming the game and graphics after all, and they did both Soulcalibur and the Tales games - both which have lots of fan service.
In Brawl, she winked when she did her back throw butt bump. That wink has seemingly been removed for this game, going by that pic when she butt bumps Fox.
Funny fact: one of the first images of Peach they showed in Brawl was that exact move (her backwards butt bump), but then she butt bumped Mario and not Fox.
Another funny fact: way back at E3 2001 when Melee was showed for the first time, they had a video reel in Nintendo's booth that showed off Smash. That video reel was NOT the same as the one sent out to media later. This reel had Peach running away from Bowser on the Mute City stage, and the camera was so low you could see her panties as her running legs kicked up her dress. I was there and I'll never forget the surprise when I realized Nintendo was actually showing off Peach's panties!
I suppose a thong would be too much to expect, especially considering how they covered up Peach in winter sports games ever since the SSX on Tour thong reveal. In SSX, she had just her minidress. In later winter games, she did not have bare legs anymore and you couldn't see her panties. I'm pretty sure they changed her clothes like that as a reaction to the thong issue.