You should add the feature to export isobath contours as an MBTILES output. This file is becoming the defacto standard for capable mobile device apps. You already have the capability to export side-scan to mbtile, why not contours as well?
Also, you should have an option to perform a "What you see is what you get (WYSIWYG)" colors export. First time I did an export of a KMZ file, I spent a ton of time honing the colors to exactly how I wanted them, using depth scale settings, etc. Then when I go to export, none of that mattered. I can get around it now by editing the exported KML code to get the exact color palette I want, but it shouldn't be necessary. Why have all the color palette options and depth scale configurations when they don't matter for exports?