Before raising Nezhmetdinov above world champions, take a look at the games he lost. Nezhmetdinov played some spectacular games, but his constant search for brilliant sacrifices meant that he also lost some games in shockingly one-sided blow outs.
Morozevich and ivanchuk play in a similar style to Nezhmetdinov but both play better middle games.
Nezhmetdinov isn't anywhere near Tal.
Perhaps the closest we currently have to Nezhmetdinov today is Timur Gareev. Gareev is capable of playing incredibly beautiful and incredibly naive games.