Sad statement - where is boxing's next great fighter? There is nobody current, and nobody in the pipelines that will match Ali's greatness. Maybe DLH (cough cough).
Roy Jones 1993-2003 was in the same league as Ali in terms of ability, though obviously Ali is far ahead in terms of greatness because his resume is so much stronger than RJJ's. No-one since has came close, and I don't see any prospects who look like they could reach that amazing standard. Hopefully one will come along soon.
A wonderfully skilled fighter, but not up there with Ali IMO. The next tier down, or more likely 2 tiers down.