I don't know about that, because it does seem to be ''WAAA. GENERIC ENEMY. WAAAAAAA. HE STOLE SPOT FROM -insert character who isn't prevalent or even that iconic-"
I mean I have my issues with him personally. I'm planning to pick him up and love him, but I think it would have been nice to see Toad or Paper Mario at least before him. Or of course Geno, for the fan want of it all.
But as it stands a lot of the complaints I'm seeing do seem to boil down to ''I hate him because I think he's generic and doesn't deserve the spot but -character from dead franchise-, -one off appearance character here- does!"
Juvenile characterization aside, that still doesn't mean they think he's some unknown character. It's strawmanning to suggest peoples' issues revolve around a lack of prevalence when the complaint is that he's a generic enemy and another character should've gotten in. Nowhere in that complaint is the issue of recognizability raised, it's a leap in logic to reach that conclusion.
Because, again, no one is conflating being generic with being unrecognizable. Except you, I suppose. I would task you with finding someone who claimed Piranha Plant was some obscure character. People take issue with its generic nature because so far, unless the character is a Pokemon, Smash has been devoid of grunt enemies. People are opposed to the idea because it goes against the standards of Smash as they see them. I'm not defending those opinions, because they're subjective, so don't bother arguing with that part. I'm just explaining the differing perspectives.
And I wouldn't contend with that last part, but you do see how that's not the same as saying he's obscure, right? Being generic and being unknown certainly aren't equivalent terms, and assuming anything past that is putting words in peoples' mouths. Let alone generalizing everyone who takes issue with the character as being under the impression they aren't well known.
actually where has he been the past few days?