Best War2 player of all time is a loaded question since theres been different "best" players during each era, and what makes a player greatest is a subjective question..
When I first came to Kali95 in 1996-97 the "best" teams I played against were Azteca/Metal, DethWlkr/Stalker/DethWish, but you had many other REALLY well coordinated teams potentially with less skilled players like Pimster/Guan-Yu/Watje (the hehehe clan), IN clan (Incinerate, who I met at Foxwoods Casino ironically, Tillerman, etc), the FearDaUPS~ guys were really well coordinated, a lot of this game was teamwork skills not just individual skills.
Later on when in Kali and when BNet edition came out the Divine Intervention guys were the best, King Hillbilly/Punkash were the most dominant team the game has ever seen, but there were SO many good players anyone could be beaten at any time, even my lackluster skills could win a game here and there against those guys.
The difference I see in the greatest players of all time was their ability to play with lesser skilled players and still win. On that front, Punkash was the clear best player to ever play the game with Nerzyman very close behind, I played 100s, maybe 1000s of games with those guys and they knew how to carry, instruct, and literally tell you almost unit by unit how to help them win. They made the guys they played with better, which IMO is what makes a great player. As good as guys like KHB, Azteca, and many others were, they pretty much cherry picked their allies, only played with the best of the best, and of course won a ton, but they werent passing along their knowledge and helping others be better.... maybe that was the strategy, keep everyone else a step behind. No doubting how good they were of course, but the egos and trash talking of lesser players was a bit nauseating.