Oooh I did not know that - I did just have a read of the description for it though and confirmed what I thought in that it is a complete voice.
I don't think you necessarily need more, but with the envelope VCA combination I assume you are looking for different flavours of envelope which is why I suggested the things I did - does that make sense?
If you are happy with the sound and are looking for ways to extend the functionality, I would probably go for more modulation, maybe some S&H, maybe another flavour of wave folder and definitely some kind of FX, my natural choice would be a nice complex delay... DLD, Rainmaker, Tapographic, 1-Bit, Chronoblob, any of them are awesome and will let you do incredible things with those bongo hits, have a listen to this to hear the effects you can get with a delay, my favourite is the Berlin style syncopation where the delayed notes interplay with the newly generated notes... magic!