So now that he's on the table again, here's my entire thoughts on it all: It's all or nothing, for Travis.
Why does Travis deserve a chance to be in Smash Ultimate?
Since people love to use the arguments of relevance with Nintendo, No More Heroes is a series that started it's life with Nintendo, having all of their games appear first and foremost on Nintendo's consoles. Yes, No More Heroes 1, and Travis Strikes Again are being ported to other consoles, however it's been stated that personally Suda prefers the games to be played on Nintendo's consoles due to the motion controls. That's the way it's meant to be played.
Suda is personally friends with Sakurai, and jokingly has bugged him with including Travis into Super Smash Bros since Brawl in 2008. When Brawl was being hit with delays and the like, Suda provided some of his staff to help with production of the game which lended him a special thanks in Brawl's credits. Asking for their character to be in is not a surefire way to get included into Smash, but Snake was added due to similar reasons. Who's to say Sakurai couldnt do the same for a friend?
Travis could provide a unique moveset and playstyle in Smash, especially compared to other swordfighters. He has a lot to draw from his games, different beam katanas that provide different fighting styles, skill chips that allow him to do things like star wars force choke opponents, shoot down a huge laser, or even stun enemies for a short period of time. In hindsight, he might play a bit similarly to Hero, who's normal attacks are sword strikes but the special moves are completely unique. Travis also uses wrestling moves, and while this might only translate into his throws; Incineroar is the only other character to have these.
They can use Smash to promote No More Heroes 3. You can say that the promoting aspect is a silly thing to bring up, but this is apparent for a lot of characters. Just look at how much Odyssey and Breath of the Wild things are in Ultimate. Before, he could've promoted Travis Strikes Again, but No More Heroes 3 is a mainline title which was even officially revealed via a Nintendo Direct. No More Heroes 3 is also Switch exclusive (for now), and theres the possibilities of No More Heroes 1 and 2 being ported to Switch.
The violence is a non issue in denying Travis a chance to be in, since there are already characters from mature games. Even though the counterargument is "Travis wouldnt be the same without the gore" or "No More Heroes is popular because of it's gore", those are inherently wrong statements. Yes, NMH is a gorey game with a crazy amount of swearing and lewd aspects. But people were attracted to the franchise due to Travis as a character. He's an otaku that plays videogames and also loves wrestling. Travis is a dork, Travis isn't cool, he only thinks he's cool. That's why he's the No More Hero. TSA was a game that lacked gore and it was completely fine. Travis can shout out whatever dorky attack lines or videogame references he wants without swearing. The violence and swearing are an non issue.
Suda wants this so bad. I think a lot of fans want it very bad. I personally have been waiting since 2008, back when I had a Travis skin on Ike in Brawl. Since he most likely has a second chance of being added, all I can do, is believe.