This sounds like a good idea, but there are a few things you may or may not have forgotten about (I'm going to point them out anyways):
There are always outliers, as in people who are outside the general curve.
The mental/physical age of a person might not match their actual age.
A person might like/dislike wavedashing (and other stuff) for a logical reason, and this could occur in any age young or old.
Age might not be the determining factor here. The problem might be misinformation/misinterpretation of one or both parties involved.
There are always exceptions.
There might be people who love ad-techs, but are too lazy to practice them.
There might be people who hate ad-techs, but use them because they believe it's the only way to compete.
People might lie or give incomplete information.
I'll just stop the list here.
I'm 18, and I use advanced techs. I think they aren't cheap. In fact, I believe they are necessary for Super Smash Bros. SHFFLing, WDing, wall/floor/ceiling techs, DIing, and all the others are no different than all the other advanced techs and shortcuts in other fighting games. Those other games have advanced techniques as a way to improve your character past normal limits. If it weren't for things like this, everyone would know how to defeat any character and know their every strength and weakness, their limits, and what to guard against. Advanced techs like SHFFL'ing and wavedashing solve this by giving players a way to improve their characters, playing styles, and overall skill level. They're not required, and in fact there are several people who play at top pro levels without them, but they are a good way to break up the monotony, even out the flaws in each character, nullify the overpowered-ness of others, and allow people to get insanely good at a game when they otherwise wouldn't be able to. AT's take incredible precision, and only someone with absurd reflexes and mind-bendingly steady hands can pull them off 99.99% of the time (and yes, even the best still make mistakes).
As a final note, WD isn't an end-all, I win every time I do this technique. The only thing WD allows you to do is move forward or back without dodging. That means you don't get the benefit of the invincibility frames that dodging gives you, contrary to popular belief. It can only move in two directions (forward and back), you're still vulnerable to attacks, you can't wavedash up in the air, you can only attack about halfway through a wavedash (something to do with the landing animation frames... characters with longer WD's have a longer sliding distance, but the lag time at the start is about the same as everyone else's), and a slow attack out of a WD is still a slow attack, but in a different position. All in all, the only two benefits gained from wavedashing are a higher mobility and a rather sizable intimidation factor. People think that you have to respond to someone when they WD, which psyches them out and causes them to make mistakes which lead to defeat (the primary one being 'moving'). The truth is, you don't have to respond. In fact, it's probably better if you just sit there and let them get in range of your longest attack, because they aren't invincible while WD'ing. I can't begin to count how many times I've faced someone who thought wavedashing made them unbeatable, only to watch them slide in range of Marth's F-smash and get KO'd at 39%. Also, since WDing can only move laterally and doesn't offer invincibility frames, I've seen people deal a lot of damage with high-speed projectiles like Fox's laserrs, Falco's blaster, Samus's missles and charge beam, and even Pikachu's thunder jolt (the bounciness and terrain following properties make it rather hard to WD away from).
However, this doesn't apply to truely skilled players. At the most, it'll make them change tactics (flexibility being a fundamental part of skill). Then again, if the player was that good in the first place they'd probably beat you even if WD'ing didn't exist. But that's why they're the best, huh? =P
All in all, wavedashing is certainly not all powerful or an instant win condition, but a good player can put it to use. That's why it's still around.
The above rant is my personal opinion. Feel free to disagree if you want.
(Prime Corruption for my birthday....yummie....)
