My humble suggestion here follow
- possibility to open a "terminal"
- possibility to configure background and foreground color, that means black over white (default), but also white over black. In some case, the last mode could be better.
About Pocketbook pro 912:
- zooming via stylus in a flexible way, as Onyx Book M92 (see this video
to have a concrete idea), with the possibility to come back quickly to the previous view.