I understand making an instrumental for an instrumental's sake, but you don't want to fall into the trap of continually making unusable instrumentals instead of improving on your ability to make workable beats. This is assuming that you want to be primarily a hip-hop producer. I disagree about having more changeups and such if you were going to be putting a vocalist over it, a lot of the best rap production is very subtle.
So regardless of if you in the end actually intend to turn the instrumental into a song, you should still think of it as if you were. If you're playing the beat back to yourself and it sounds like it would be difficult to rap over, chances are there's something you could change to improve it. The thing about this brass kit, is although there are some workable sounds, they do not stack together that well. The kit shouldn't be used by itself, and i think some more percussions or bass or something would make your songs more well-balanced.
