As someone who does a lot of editing and mapping for sample instruments, I can see a ton of potential for Soundbox as a fast loading, quick alternative to Kontakt, which has become pretty bloated over the years.
But some further sample editing and mapping features would be amazing! One that would make my own life a ton easier is automap based on a section of a sample filename, but I appreciate that seems like rather a complicated feature to implement now.
But a feature that would be very helpful very quickly would be a way to zoom in vertically (ie make the amplitude graphic larger without actually affecting gain) so quiet samples that barely show up on the screen are easier to edit their start/end/loop points.