Great questions.... Based on the accomplishment factors (also weighing caliber of opponent), I'd say that K-1 Champ/Pride Grand Prix Champ Cro Cop should DEFINITELY be on the list, as should UFC/Pride Champs Big Nog and Dan Henderson, Hell even Mark Coleman I'd have to include for his GP, UFC & Pride titles.... In WMMA, if there was no Gina Carano, there would have been no Ronda Rousey, and Cyborg is arguably the WMMA GOAT (I think she due to longevity of career slightly notches above Nunes, but ultimately Nunes will be the GOAT).... JMMA carried the sport in the dark days, and there was no bigger star than Sakuraba.... and Kid, he had endorsement deals, and was a star in a way that Conor is now, before anyone thought that was possible.
A lot of that dudes list I can agree with (the GSP's, JBJ, Spider.... The typical picks).... But I'd remove Tito, Stipe, Couture, Hughes, JJ, even (controversially) DC, and add most of the people on I mentioned.
Well if you tweak the parameters enough, anyone can be the most influential. When we bring in things like PPV numbers, earnings, influence, marketing, endorsements, and even belts, we're getting into things that are largely determined outside the cage and have little to do with fighting. That guy said "most accomplished," which I think we can reasonably assume means in fighting. To me, the purest lists we can create generally come down to who beat who and when did they beat them. Cyborg, for example, only beat two truly competitive opponents in her whole career and they were Carano and Holm. She only had longevity because of the long time gaps in between her fights or because she was in a division of one. I don't think we can say the same for Nunes or Joanna, even though we can still say that WMMA is in development. They've had aggressive schedules since their careers started and they've risen to the occasion more often than not. When we look at Sak, he had some awesome wins, but besides there's a lot of screwiness in his fights with guys like White, Newton, Conan, Kimo, Belfort and Shamrock. The other part of his career was demolishing the Gracies, which was meaningful at the time, but when you put their careers into context, how meaningful really was it? Sak moved directly to journeyman status once they actually built a division around him. There's no way realistically we can compare someone like him to Jones or DC. It's almost like they did two completely different sports.
Crop Cop is a more complicated story. His Open Weight GP win was great, but he didn't beat Fedor. His run in the HW GP before that was great, but he didn't beat Big Nog. His Rizin run was awesome, but in more of a spectacle way since his competition wasn't exactly great. And he wasn't as accomplished in K1 as say Mark Hunt who is absolutely the most accomplished kickboxer to ever also fight high level MMA besides Reem who I'd probably rank ahead of both of them. Or Werdum who beat Hunt, Reem, Fedor, And Velasquez even though he lost plenty also. Stipe at least won the belt twice and defended it more than anyone else, and not just the UFC belt, but also the lineal HW title that goes all the way back to Shamrock/Severn or Royce/Howard or Coleman/Severn or whatever route you want to take to get there.
Hughes and Couture have seen their legacies wane a bit. Couture lost almost as much as he won, but Hughes is probably still the #2 WW of all time and is one of only two men on Earth to beat the #1. I'm fine with leaving him off a list of the top 16 fighters, but I don't know if it would be for Kid, Sak, Cyborg, or Hendo. Hendo probably has the closest claim because of who he beat, but he also lost a bunch, which degrades him a bit.
I loved MMA back in the day, but evaluating fighters accomplishments retrospectively under different rulesets against modern MMA is hard. It's always fun though and is one of the good things about video games.