Regarding better usability:
Do you already have a good solution for showing a large number of menu items? In emulation station it's already a pain to navigate through less than 20 items as you only see 3 items at a time.
On the RS-97 there could easily be 30 emulators/systems and 70 games/apps you would have to scroll through!
I think the emulation station ui was only designed for a few items and is very limited in that regard. There should be more items visible at the same time and some kind of hierarchical structure.
Perhaps a folder concept similar to the Playstation 4 menu on top of your current concept:
- select the system menu item 'Nintendo' (or 'Games' or 'Apps')
- press A or down to select the item
- the system image slides up a bit and shows all sub items in a horizontal list
- pressing B or up closes the sub items and goes back to system items
- select the sub item 'Game Boy' (or 'CZDoom' or 'Explorer')
- the system image and sub item image slide to the top (side by side) and a file browser is shown below
Basically all of this could be done by modifying GMenu2x:
- sections would move from top to the center of the screen
- sections as a scrollable list with larger icons and matching backgrounds
- not only 4 sections but: Consoles, Handhelds, Amiga/Atari, Arcade, ... Games, Apps, Settings
- links as horizontally scrollable list just like the sections
- bottom bar (battery indicator etc.) could be reduced and moved to the top
- button hints could still be shown at the bottom, but slide down after a few seconds
What do you think?