Carter 1 and 2 are classics. Not flawless albums, but classic ones. I think the idea that classic has to mean flawless is misguided, or even the idea that there is no real definition to classic, but similar to how classic movie is used.
Carter 2 defined an era, it set trends, it had great lyrics and production, a central theme, Wayne was never more focused. It was creative, innovative, expanded on the theme and execution of the first one. Wasn't stagnant, or a sequel in name only. I don't even listen to this shyt that much, but the memories are timeless and it's an actual quality album. Get Rich or Die Trying is a classic too, but it's a few steps down from something like Carter 1 or 2, when you talk about artistic expression, skill and creativity. 50's debut is a total formulaic major label album.
He fell off right after this to me, solo album wise. Unless you count The Los Sessions. C3 was iconic in it's time, but there's hardly even 5 tracks I like.