So I hadn't really followed the general system changes in Smash 4 until now, especially since they're not conveniently compiled in one place for people to check, and I have just read that the landing lag for all aerials has been increased. If that's true, then that's quite a nerf for Peach, more so for her than other other character since she is so reliant on them coupled with her float.
On the other hand, this could have been predicted tgiven how ******** her low landing lag was on her aerials in both Melee and Brawl. She could literally infinitely shield pressure her opponents with float canceled aerials and end with Dsmash in Melee and for Brawl standards her aerials were very safe, especially her Fair.
Anyway, it's still too early to assume anything. Her aerials may be spared relative to the other characters since she revolvs so much around them. However, I frankly doubt she will receive special treatment, so she will probably receive some other kind of compensation. Anyway, we will probably have to kiss goodbye to our lagless aerial pressure.