Top heavy category almost to a fault depending on one's perspective. People argue that the Grammys look at whos popular and run with that. Which is fine but that shatters the whole Esmeralda Spalding vs Bieber theory a couple of years back and the show isnt about promotion but rather going with the status quo. They may take more risks or surprises in other categories (Im sure fans of other genres may disagree) but the Hip Hop main categories have always been fairly predictable.
The Roots getting a televised win for best rap/sung collabo in 2000 was the lone exception.
But its pointless to complain about it. For your fav just to nominated is recognition enough and while it would have been nice if say a Nas won and that there was genuine buzz for him, its not a big deal. Just move on and build off the clout for more music.