I’m honestly super surprised you guys literally only talk about Ninja Gaiden in smash when you guys talk about Koei Tecmo on switch when most of the KT games on switch are Dynasty Warriors. So by Smash speculation logic, you guys should be talking about a Dynasty Warriors character. My guess would be Lu Bu since he’s pretty popular. But I guess “legacy” is more important to speculation
It was awhile back, but I'm on record for hoping for either Mocchi or Suezo for a Koei Tecmo rep. A few others hoped for Monster Rancher as well.
You're right, though, that people tend to favor the Legacy of a series when considering possibilities. Sakurai had said on multiple occasions, "Smash Brothers is a celebration of Gaming' (or rather, it was a Celebration of Nintendo and now its moved on to gaming in general) so people tend to see that and think "well, of course its only right to celebrate gaming with the most recognizable icons of gaming". That's why you've got reps from really well known series like Cloud (repping Final Fantasy) and Hero/Erdrick repping Dragon Quest (two pinnacles of the RPG world), Pac-Man repping the most well-known Arcade game to ever exist (the Pac craze was apparently pretty nuts), Sonic as he was the most well known gaming mascot aside from Mario in the 90's, Ryu because Street Fighter is incredibly well-known and practically the go-to thought when people think 'Fighting game', and others.
Of course, you've got the occasionally statistical outlier like Joker & Bayonetta who, while coming from a great game & great series, is still from a series that was more niche up until recently. Its additions like those (and the aforementioned) that are the reason peoples' speculation leans more toward 'Icons with Legacy' to join the others. "They've got Steve, Cloud, and Sonic to rep PC, Final Fantasy/Sony, and Sega; why not Master Chief for Halo! He'd be perfect!" is the general thought. It's hard not to see their point when you've still got near universally recognized characters like Doom Guy, Master Chief, and Crash not in while the rest have been added. That's why speculation tends to go in that direction than more niche titles like Monster Rancher, Ape Escape, or something like Tomba!.
Unfortunately, that also includes Dynasty Warriors. I think for warriors, though, it's more that its gameplay formula is more recognized than its actual series. There are so many games that use its formula (Fire Emblem Warriors, One Piece Pirate Warriors, and Persona 5 Scramble to name a few) that we're to the point where its almost its own genre of game. Given that, I don't think its impossible for it to get a rep since its gameplay spawned a thousand imitators, but that may be a reason why these boards (and others) don't usually consider it in speculation. They see it as more of a genre than its own title.