I’ve seen some people who really wanted Takamaru as a playable character in Smash, but I really never thought he had a shot. He had one game 28 years ago that didn’t sell well and wasn’t even released outside of Japan until this year. The only reason most people even know about him is because of his game in Nintendo Land, and I think that only happened because the dev team made a ninja minigame and then slapped Takamaru’s name on it to give it some connection to Nintendo.
And yeah, you could argue that the Ice Climbers only got one game in the ’80s and they still made it into Smash, but the difference is that their game was released internationally and received moderate success. Plus, most of the reason they were added to Smash in the first place was because of the unique playstyle they could offer.
Bottom line, Takamaru’s gonna need some kind of revival to make it to playable status.