imho this is actually a nice little rack. If you are just beginning you have all you need VCOs, VCFs, VCA, a sequencer, and some FX. You will of course grow into your own way of using them together and you'll get more stuff soon enough. I suggest as you do to get more simple VCAs and proper ADSRs. Maths is great in a pinch, but good ADSRs open up many new paths for modulation. Can't wait to hear more!