One cool option would be the ability to add custom config values in the manifest that are tied to a new tab in the UI when editing an app. These options can be mapped to environment vars which are available to start.sh. For instance, for Minecraft:
Another point here is I would like it if these options were available when initially installing an app. This would allow someone to initialize an app with even more options out of the gate.
If this is already possible or has already been requested, I apologise for not checking well enough. I used Minecraft as my usecase but I'm sure this can be applied to other apps with simple toggle config options. Makes for a slightly better user experience.