Roy Emerson being on that list pretty much invalidates it. Emerson was an amateur player who peaked in the 60s when most of the best players were playing on the pro tour; if you include him, then you have to include Rosewall, Gonzales, Kramer, even Tilden, Wilding, etc. There were literally dozens of guys who were better than Emerson.
Laver is impossible to rank because his career saddled the Open Era. Same with Rosewall.
I also don't like Agassi over McEnroe. McEnroe was a far more dominant player in his prime, and his overall career numbers are better.