Jon Jones is in the discussion for best fighter ever. The notion that his legacy is overrated is not one that should be taken seriously.
You want to argue that Rampage/Shogun were past their primes when he fought? Fine, fair enough. But he fought Machina, Rashad, Gustafsson (twice), DC (twice), Vitor, Teixeira, Smith and Santos, all in their primes. He fucked up Thiago Santos's knees so badly that he's been a complete shell of himself ever since.
Not only that, but the majority of his fights were not all that competitive. Outside of the Gustafsson fight & the Reyes fight (which I thought he lost, btw), none of his fights were competitive. They were one-sided.
As for the drug testing... Couldn't give less of a shit. All your favorite fighters are on some type of shit too, they're just better at evading the drug testing. Don't let UFC propaganda fool you.