Really bored so making a list of everything that smash 4 needs to be at least as good as melee:
L-Canceling
SHFFLing(short-hopping, fastfalling, l-cancel)
Wavedashing
dashdancing
Teching
Ledge tech
crouch-canceling
power shielding
power shield reflecting
smash DI
jump canceling:
-JC grabs
-JC shines
-JC up smash
-JC up-B
Walljumps
chaingrabs
jab resets
ledge drops(dash drop, shield drop, isai drop, pc drop)
edge-canceling
character specific skills:
fox/falco shorthop lasers
fox shorthop double laser
fox falco JC shine as said above
fox/falco illusion shorten
fox up-B sweetspotting
fox/falco waveshines
marf's reverse up-b
marf's side-b stall
when playing against marf, lightshield instant edgehog
sheik's needle cancel
sheik's up-B ledge fakeout
sheik's needle air pivot
sheik's infinite ledge stall
samus' infinite up-B tech
samus' super wavedash
samus' infinite down-b recovery
Icies Wobbling
Icies desyncing
Falcon's gentleman(actually, an easier gentleman would be awesome)
Falcon/Ganon Down-B jump reset
falcon/Ganon Eddy spike
pikachu's double upward quick attack
a lot more shit that I can't think of atm
I DUNNO MAN NOT LOOKING GOOD FOR SMASH 4