Honestly, when rappers try to "cash in" on the current trend, I think it alienates them because that trend is bound to change. Once it does, and they haven't "blown up" yet then they are stuck with a dated song, or album that'll never see the light of day. If it does, then the folks they are trying to present it to will laugh and say their creation is old.
I agree with kev. The whole point of being an artist is trying to separate your work from everybody elses. You have to create a signature sound you can call your own.