I expect Nas to honestly get one classic (Illmatic), but I voted Illmatic, IWW, and Stillmatic. God's Son is just a good cd, and even if Lost Tapes had been included I couldn't give it the classic label (mainly because the impact wouldn't be there).
I won't speak on Illmatic, but I think IWW is right there with Illmatic lyrically minus Nas Is Coming. Honestly, I'm sure this is an unpopular opinion, but I always felt like Black Girl Lost was the one song that didn't fit in with the album's theme or content. It wasn't exactly a single nor did it introduce the world to what would later become the Firm (Nas Is Coming/Affirmative Action). It just seemed like a dope song that just happened to be there. Just my opinion, and i'm criticizing just for the sake of it. I honestly feel like in many ways, Nas stepped up his song-writing and lyrics on this album, but it's just not as "perfect". Another issue with this album I think is that for better or worse a lot of songs "blend" together giving them a singular feel unlike Illmatic/Stillmatic where every song more or less has it's own identify. Some might argue that it makes the album feel more cohesive, and I can't argue against that. Just my observation.
With Stillmatic, I can understand if someone doesn't appreciate the quality of a few songs on the album, but honestly other than My Country, I think it's great from front to back. I've never expected a classic album to be "perfect" though. I might understand criticisms of Rule although it wouldn't be an opinion that I share. I've always felt that song-for-song I get way more excited about listening to Stillmatic over It Was Written the only difference being that the weaker songs on IWW are scattered throughout the album, while the argument with Stillmatic has been that the latter half is less consistent than the front 9-10 tracks. WIth that said, it may not be a popular opinion, but I think the highs on Stillmatic are just as high if not HIGHER than those on IWW (not lyrically, but from an artistic/song standpoint). Factor in the beef with Jay/Ether, and this album represents a monumental moment in hip hop that I think just gives it the nod in spite of consistency.