All this discussion of whether it's a "glitch", or "exploit", or "cheat", is completely pointless. Here are the facts:
- In case you didn't know, there are multiple versions of SSBM. Between each version are several minor differences, such as balance changes and bug removals. Samus' extended grapple and Bowser's flame cancel are two examples of things that were removed from later releases of the game. If Hal didn't know about wavedashing before the game's release, they almost certainly would've learned of it later, and yet despite all the other "fixes" in subsequent versions, wavedashing was left in.
- Wavedashing is a large part of the reason for this game's depth. If they remove wavedashing, they will lose a large part of their fanbase, the tournament players, while the removal of wavedashing is not likely to attract any new players to the game. Therefore, Hal has nothing to gain by removing wavedashing.
It is for these reasons that I believe wavedashing has a very good chance of reappearing in SSBB. In any case, nobody can possibly know for sure at this point, and in fact, Hal themselves might still be debating the issue, since the game is a long way off. Nobody can claim that they know whether or not wavedashing will be in SSBB. You can, as I did, state reasons why they should or should not include it, or why you think they will or will not include it, but ultimately these are nothing more than opinions.