Last year I specifically left a mixtape (Friday Night Lights) off my best of lists, arguing that it didn't qualify because it wasn't an album. But given the direction of music lately I'm not sure it's particularly logical to do so; a mixtape of new, exclusive music is certainly an "album" by today's standards.
Conversely, my AOTY is a mixtape: House Of Balloons. And my hip hop AOTY is a mixtape as well: Section 80.
I would also agree Cole's album is quite average, and it would be easy to make a case it's not a top ten hip hop release. It has some of the worst production I've heard on a major release this year; just empty, boring production. I was listening to Take Care yesterday, and while I'm no big fan of the album there's no question the production is good. It sounds like a full, lush piece of work that has a consistent sound sonically. Whereas Cole World feels like a handful of forced club songs (that don't bang) mixed with piano tracks, some horns here and there. It's not a bad album, just disappointing. Dude needs to either take a lesson on EQing drums or get a good producer to handle his stuff.