It's all based on opinion.
Whenever these types of conversations airse I often have to think this is really what it comes down too.
I mean I use to fight Bighorn many years ago and I thought this dude was the best I've ever seen. I never saw him in the MA, and every single time in the DA he would graciously kick my arse and even let me film, and he taught me a lot about ACM in the game.
It's almost impossible to mark "great AH sticks" because everyone has their own interpretation of how they percieve there own greatness compared to others greatness. "He stays alive all the time" he's great!". "He is the best dueler in the game" he's great. "He gets the most kills" hes great. But all of these single things are marked by players who have different ideas about what they are trying to accomplish. The guy who gets the most kills may not be the best dueler in then game. You may stay alive the longest, but not really get that many kills.
I think it just comes down to experience and overall knowledge of the game and the different aspects of which you choose to "be great at".