I don't completely agree with your statement. When you rate a character you have to take into consideration every aspect of the game and the characters into consideration. Duo Lon is a great point character but he has multiple weaknesses and isn't very versatile in team positioning so he should be ranked lower than Mr.Karate who is also an amazing point character with very strong tools, less weaknesses, and is good in any team position.
The top tiers being dominant in this game is a combination of their good tool sets, few weaknesses, high damage for little resources, and versatility in team order. They generally have favourable match ups against the majority of the cast and require less time to learn and be effective with than other characters in the game.
This being said, I strongly believe that KoF's 3v3 system and overall game mechanics help mitigate tier disparities to a certain extent. Top tier characters will always be commonly played at high level in any game but KoF is one of the rare games where you can see low tier characters do well in tournaments.
Toshi winning that Peruvian tournament and going even against Bala with EX Iori/Athena/Kensou and TC| Pako getting 3rd at SCR with Duo Lon/Elisabeth/Mai are some of the best examples of this.
Of course the universal quality should be accounted for. Even if Karate and Duo Lon both scored, say, 95/100 on "point character goodness", Karate should still be rated higher because of his extra flexibility to stretch into other roles. That's 100% as it should be.
Agreed 100% on the rest of the post.
The thing I'm trying to say here is, though, that we have characters like Duo Lon who's absolutely splendid on point, and atrocious as an anchor. How the hell do you put characters like that on a single tier list? Rate point performance only? Or rate anchor performance, or some odd amalgam of the two? Even more importantly, how can you begin to compare him to someone like Claw or Vice whose reason for existence is to be an anchor and turn meter into a dead character off a touch? When they're built to do different things and usually are not even competing with each other for a slot on the team directly? Like, "Is Duo Lon or Vice better" is a non-question to me. It's just invalid. Which is better as a point, battery or anchor is a question where an answer can be found. And to each of those, we can say that Karate is probably a bit better, and have that answer be a valid one.