Don't get me wrong, I actually think Yoshimitsu is a perfectly fine suggestion, in fact, I didn't even know he'd been submitted and was just using him as an example.
Are you one of those people who unironically uses Scrimblo Bimblo?
You're mistaking "sales numbers" to equal "iconic" - sales numbers definitely play a part, but just having big sales alone isn't enough to an iconic character make. There's literally dozens of factors that make that.
Smash invites don't just get handed out to every tom, ****, and harry that exist in video games. There need to be some boundaries so that the roster doesn't get filled with characters like Buck Bumble, Android 21, Tim from Braid, and Billybob Tekken. Pushing those boundaries from time to time isn't a problem - but knowing the line between what's really has status as an icon, a substantial fanbase (not just in Smash speculation but their own series as well), and interesting moveset potential, and what quantifies as just "for the sake of memes/pissing people off."
Even with the character submissions I personally dislike in this thread, such as Grovyle/Celebi, Crazy Dave, and Marin just to name a few - I at least see some form of merit in including them. But with a character like, say, for example Neco-Arc, who actually is a fighting game character (and a ****post at that) I literally cannot see merit in including them as a fighter in an official Smash title, which may I remind you, this is supposed to be (hypothetically). As a fighter in Crusade or SSF2? Absolutely. But if we're trying to pretend this is supposed to be "the next Smash after Ultimate" than there should absolutely be some form of barrier to entry.