In terms of gameplay, I'd like to see recovering take some skill again, instead of being "This character can and will or just plain can't recover"
There should be separate types of tethers. Grapple Beam, Clawshot, Plasma Whip, and Sheikah Chain could tether a wall and Pikmin Chain, Plasma Grapple, Grapple Hook, and Snake Rope would home in on the ledge.
And they should be able to have multiple uses until it tries to home in on the edge and fails, at which point the character freefalls.
Water and Wind should be able to be damaging elements at the same time as certain other moves that use it would just push. Forcepushing (Gale Boomerang, FLUDD, Water Gun, PSI Magnet Ness, Ninja Teleport, Ending Blow, Wings of Icarus, Bug Spray) should reflect solid projectiles and disperse energy. Maybe pushing should also be able to trip.
Random tripping is bs. Maybe put a little bump on every stage (randomly placed when the match starts) and if you begin a dash there, you trip over it.