Wavedashing as a polarizing force
Wavedashing is a polarizing force, creating two distinct groups: Those that can and those that cannot. With Melee out four and a half years, wavedashing has become widely known. The question comes up in designing the next game as to whether or not to consider wavedashing when making and balancing the game. Obviously if it is to remain, it must be a factor in balance. Relative power and utility of character's moves will be weakened to compensate for added functionality gained through wavedashing.
Now up to now, this is all well and good. But consider the friendly casual SSBB player who sits at home, playing with friends. He may or may not have heard about wavedashing, but he doesn't use it, either due to lack of skill, lack of knowledge, or what have you. Wavedashing now affects him. His favorite character is not performing up to par with that of his friend's character, who seems better in every way. Unbeknownst to him, he has a very potent character, but only potent when used with wavedashing.
The expert Smasher may say, "There is no problem, this player simply needs to learn to play the game or pick a new character." This mindset creates several problems. First, there is likely no official description of this technique. Sure, he could discover it on his own, slowly perfecting it and attaining a higher knowledge of the game, but this is outside his prowess. Second, it further polarizes the characters into "casual friendly" and "expert only" categories. Many characters become 'Pichus' in a sense; the handicapped characeter in the hands of the majority of those who play the game, not performing up to par with others.
Consider one of the major aspects wavedashing adds to the game: Backwards movement while facing forward. This plays an important role for any pro Smasher's game. But simply put, it's unintended. Characters do not have the normal ability to moonwalk for a reason. You may say, "But it adds depth and strategy to the game." This is certainly true, but depth and strategy cannot go without limits. As a very blatent example, consider if there was a certain button combination that allowed characters to have free flight. This certainly adds depth and strategy to the game. But it makes the game outright stupid. The game shifts away from its intended functionality and shifts towards who can free flight the best. Wavedashing has similar residual effects. It removes consequences from certain actions, speeds up other actions, and gives a level of control that wasn't intended.
In closing, wavedashing is an unnecessary complication in the game, which acts equally as augmenting and restricting force. While it opens up new possiblities in the game, it stifles further development, as every new addition must be seen in the context of what it becomes with wavedashing. My concern is that wavedashing may become incorporated into the game so heavily that its playability becomes limited without the technique and that other great ideas (character skills, game mechanics) may lose potency or be left out completely because of their interaction with wavedashing.
However, if wavedashing is transferred to Brawl and left as an invisible effect to balance, then I concede that there is no problem.