I'm not sure why people are using Waluigi's origin as Wario's tennis partner as a jab against the character. Technically other Mario characters were also made to fill a vacant spot. Mario was created because Miyamoto couldn't get the license to Popeyes and he wanted a quick replacement. Luigi was made to fill a Player 2 slot. Wario was made because the development team didn't like making a Mario game and wanted to make a villain that mocks Mario.
The reasoning for the creation of these characters is silly, but they are beloved to many people and have become prominent after their debut despite the silly reasoning for their creation. Characters evolve after their creation, and Waluigi has become more than just Wario's tennis partner throughout the years. He's a **** Dastardly type character that loves to be mischievous and cheat. If you don't get the appeal for this type of character then that's fine, but know that People love Waluigi for his character even though he hasn't starred in his own game yet, and that is impressive.
Also I don't get how memes invalidate the legitimate love people have for Waluigi. Luigi has also been meme'd to hell by his fans, is the love from his fans illegitimate as well?
It's really just an additional dig at him because I personally find him to be a really damn boring and uninspired character at this point. Like he's got some degree of a personality, but I just actively don't enjoy it and find it to be a shallow one that goes nowhere. I also don't think I've ever seen a moveset for him of any type that has interested me in the slightest.
Also, the memes specifically about him getting into Smash and people somewhat ironically supporting him just because of said memes. Waluigi has his own little Smash culture that people
who literally don't give a **** about Smash want to see him because "WAH." I'm not kidding, I've had conversations with people that has basically amounted to it. Do they like Waluigi as a character? No. Do they care about Smash? Not really. But they think Waluigi deserves to be in Smash because the funny meme told them he should be in it.
That shouldn't impact actually Waluigi fans or his inclusion, but that sort of internet culture is damn annoying and adds to me just actively despising the day he joins the roster. Again, my personal opinion and I'm not saying he should be kept out, but it all adds up to me seeing him as one of the more disappointing character choice that Sakurai could add. Like, he'd probably play
fine, but again, I
personally wouldn't really care for his inclusion.