Wavedashing certainly has potential as an idea, and I would like it implemented back into Smash.
BUT, I do not want it implemented purely as an emergent tech of airdodging. Doing that would limit the potential it could bring to the series.
Instead, I would gladly sacrifice one of the shield buttons to make it a "wavedash button". Just press the button, and you "dash" (not run) forward. You can even dash backwards if you hold the control stick backwards or hold the control stick diagonally downwards at various angles to adjust your dash length. Makes the move easier and more accessible to do while keeping all of its benefits.
In addition, I would also love to see waveshining be extended to all characters in a sense, where the "wavedash button" can cancel all jabs and tilts, and specials on a case-by-case basis. It would open so much opportunities for combos, akin to the FADC of the Street Fighter 4 series. It would even be largely balanced due to the knockback growth of all moves.