Off the top of my head, things that this is lacking: velocity control for each pad, a way to zoom in on waveforms and chop up samples, maybe better loop controls, and the ability to export as .wav?

But suggestions aside, as a budding hip-hop producer/hacker, I had the idea to make this but never the skills/conviction. It made my day to see that this is something actually doable, and capable of being done well.