Wavedashing isn't needed to play the game to have fun. And to be quite frank, it doesn't take anything away from casual players unless a player who knows wavedashing uses it. Although to be honest, wavedashing doesn't fit the smash "physics." However, I think wavelanding and things like "V-Dodging" definitely do fit with Smashes' physics (even Brawl).
Also, who cares about the skill gap=??? There should be a skill gap. Even Mario Party has a skill gap. If we remove that in smash, it is no deeper than that Shrek fighting game.
Now, if you want to decrease the difficulty to become better, that's another thing. But don't sacrifice depth to make the game more appealing to players who aren't that good. Instead, give them good guides to get better, let them know about all the techniques, and teach them not just how to use them, but how to use them in battle. Make it to where it is easy to learn them, a bit harder to apply it properly, and difficult to masterfully use. Literally making such things presentable, however, is half the battle.
Also, even if wavedashing is removed, there have literally been hundreds of techniques in smash bros thus far. What are you gonna do next=??? Remove all of them=???