We can't increase double jump height without increasing jump height as a whole, if I recall correctly. Otherwise I'd be pushing that as well.
Honestly though, Peach's killing options are awful. She's worse than vBrawl Sonic. >_>
You my good sir either have not played a good peach or don't know what your doing with peach. To say she is worse then vbrawl sonic is just dumb. I do admit though it seems to be a little harder to kill with peach in 4.0 then it was in 3.3
Everyone knows she is weak. If your playing peach and expecting to kill before the 150% mark then stop playing her.
Peach is a combo machine. She was one of the few chars in vbrawl who had true combos and in brawl+ she is even more amazing. Dair is probably top 5 best combo starters in the game. It really takes no more then 10-15 secs once u get a opening to get someone from 0-around the 60-90% mark. Also if your good at reading DI you can combo into fair,nair and bair.
Once u do get into kill range she has tons of options. Dthrow to jab to nair,Dair to nair or fair,Dtilt,uptilt to bair. She has so many options. Also her jab/tilt to grab options easily sets up these moves. And you can't forget about her 5 frame jab. It can get you out of so many situations.
The thing with peach is to get in there get your combo going and then get the hell out and look for another opening. While not the lightest char in the game she still dies well before the 100% mark against the heavyweights and chars like fox/falcon. But peach can also cg those chars because of the FF speed. Like i said in my other post. A peach player has to do anywhere from 70-110% extra damage then their opponent per stock to win. But since she has amazing combos this isn't necessarily a bad thing.
Also if your playing someone who is very heavy on the defense ABUSE IT. I cant stress enough how great peach's sheildattack and pressure game is. You can basically jab to nair over and over again until either sheildbreak or they just let go and take the hit. Also with her speed,floating,and turnips her pressure game is too good. You also can't forget about her edgeguard game either. If u can get a gimp below the 100% mark you are good to go for the rest of the match.
Peach really doesn't need any buffs. She is almost perfect as is. Only buff i can think of would be a slight buff to her fthrow. But someone already posted that the coders have yet to find the values to change throws. So until then i don't think peach needs anything added nd she deftinaley don't need anything nerf. Maybe just maybe making her sweetspot usmash a litte easier to connect with since she really has no combo that can lead into a sweetspotted upsmash. But thats not a big deal to me.
And no her dsmash does not need to be buffed. As a peach main in melee i'll be the 1st to say that move was kinda broken.