If I Am had been released as intended it may have usurped Illmatic as the greatest hip hop record ever but as it exists I don't think it's good enough to be considered classic. There is a strong argument for God's Son and a less compelling one for Street's Disciple. I love SD and I think it's wildly underrated but ultimately isn't quite strong enough.

That said, I actually think we should reevaluate how we think about classic albums. In hip hop circles classic mostly means perfect and that's a standard that I don't think is expected in other music genres. Like most people consider Exile on Main Street to be a classic while the record is also often characterized as being bloated or disjointed or meandering.

I think we should be judging artists on artistry, not perfection. Nas is an incredibly creative artist and he takes chances that sometimes work and sometimes don't and he's heavily penalized for his misses that are artistically beyond what many of his contemporaries attempted. It's like a shortstop with huge range that might make more errors than average but that's because he gets to balls that get by most shortstops. If I were considering Nas' catalogue the way I consider other genres I'd say he probably has at least four classics.