In my view Agassi can reasoably be ranked between ## 7 and 10 of all players which major successes in the open era.
Laver, Federer, Borg, Sampras, Rosewall, Lendl are clearly ahead of him.
Roughly in the same ballpark are Connors, McEnroe and Wilander. All three of them displayed greater peak dominance than Agassi (Connors in 1974, McEnroe in 1984, Wilander in 1988); and all three won higher caliber slams (4 of Agassi's 8 titles where down under, while Connors and McEnroe didn't play the Aussie Open for much of their careers). Agassi beats Wilander and McEnroe in terms of longevity, but not Connors. And then, Agassi had the career slam which some people rate highly, even though Connors also won slams on all three surfaces.
I personally rank #7 Connors, #8 McEnroe, #9 Agassi, #10 Wilander, but have no quibbles if someone flips these a little around.
Agassi is clearly ahead of Becker and Edberg, and also still of Nadal, but probably for not much longer.