Is this a test? Do we get graded after it from you? What makes you the expert into rating our competence in this subject matter?
I once owned the biggest SSBM Site in Germany, was wiring guidelines for it and managed a whole Smash community. I know a few things.
Yes, it is a test, and clearly you failed.
Here's the thing. It's true, wavedashing is not an intentional mechanic. Of course not - because it's
two intentional mechanics.
Whenever you land, whatever horizontal momentum you have is transferred and will cause you to slide along the ground. You might have notice this effect whenever you get hit by a powerful attack that sends you at a slightly downward trajectory - you'll hit the stage, but you don't stop there, you keep sliding, and how far and fast you slide also depends on variables like your character's traction. This doesn't just happen when you get hit, this happens all the time, because it's how the physics engine works. Now it just so happens that in Melee, the very beginning of an air dodge has a lot of speed, and if you land during this, you'll slide a fairly decent amount. This is really all wavedashing is. Speed + landing = slide.
Wavedashing is not a glitch. It doesn't matter whether or not it was "noticed" during development because there was nothing to fix. It was just the physics engine working how it was supposed to.
Here's some other trivia:
1. Wavedashing might be strange to learn to use at first, but it's really not hard to do at all.
2. The only reason why you can't wavedash in Brawl/Sm4sh the same way as Melee is because air dodges don't change your momentum anymore. However, if you can alter your momentum in
other ways, you can still achieve similar effects.
3. Wavedashing is maybe 1% of all the reason why Melee is a deep competitive game, and similarly is far from the only thing that Brawl and Sm4sh changed. Although it's certainly important to Melee, wavedashing by itself means fairly little in the scheme of things.