I concur with Big E, a 100% percent. I am tired of these pseudo-hiphop heads running around today. Laffy Taffy is a dope song, specifically, a club song, in the sense that it achieved its purpose. What defines a quality song is more than the lyrical ability, flow/breath control, beat, and the content embedded in it. D4L don't have a great flow and their lyrics are mediocre. But, the vibe is there. The purpose of the song is to make you want to dance and when that melodic pattern in the beginning of the songs begins "tan tan tan" on some 10's, if it does not make you nod your head to it or want to just bust some random move, you are not a rap fan.
As for Diaz, just because the beat sounds simple, it doesn't mean it doesn't sound good. Until you're able to understand that, you will never achieve your dream of being a producer.