More room at the top of the tier list for faster characters, lag on projectiles means characters that could do well traditionally like Samus and to a lesser extent Link + Young Link are headed for the bottom. Pichu is going to be surprisingly high simply based on movement speed. Grab range is also going to play a huge role because with TAS every frame/pixel is going to count. Yoshi and Marth are going to be high because of their grab ranges. Characters that can be chainthrown by a large number of the cast are going to get wrecked because a single grab will mean death every time no exceptions. Shiek is going to be godlike with the ability to techchase/chainthrow most of the cast until death. Certain advanced techniques like dash-dancing won't exist as we concieve of them. The only reason to DD will be so that you can quickly pivot to avoid attacks so you'll likely see more frame-perfect pivot options from single-frame dash dances instead of DD being used to bait like it is right now. Wave-dashing won't really be used as much because the aforementioned perfect DDing will replace it all but completely (jump frames on WD make it slower/worse).
TL;DR Melee will look far, far different than it does now. Sheik will be the best. Only things that will matter are movement speed, grab range, and susceptibility to chain-throws/character specific shennanigans.
EDIT:
Tier list might look something like this:
1. Shiek (Movement Speed, Tech Chasing, Inescapable Chain Grabs on Everyone, Invincible Recovery)
2. Yoshi (Parry, Grab Range)
3. Fox (Shine)
4. Falco (Shine) Could be lower due to less defensive options
5. Marth (Movement Speed, DD, Grab Range) Could be lower due to lag frames on attacks.
6. Falcon (Movement Speed, Tech Chasing Until Death, Punishes) Could be swayed either way, real reason he's on here is his speed
6. Pichu (Movement Speed, Low Lag Frames) Bottom of the top tiers, definitely arguable.
Other low tiers might be higher if I know about specific gimmicks/tech they have that are powerful but hard to pull off.