This is a place where we can wish for Thimbleweed Park changes and new features and the Terrible Toybox Gods will answer our prayers. Or not
I don’t really have the need to change something story or gameplay related but I came up with several other points:
It would be nice to have complete credits in-game (e.g. including voice actors) and accessible from the menu.
Because I would like the GOG version being on par with the Steam version.
extended text adventure
Ron said originally the text adventure should have been much bigger.
This change could be quite problematic because it would need translations, may affect the hint line, would need a lot of testing etc.
But maybe as an unsupported and English-only DLC? I know I can dream!
arcades: execute custom processes
This may sound completely unncessary but it would be really fun to use TWP to launch whatever processes we want. We could make our own arcade games using the arcade machine background. Or we could use it as game launcher for existing games like Maniac Mansion or Resident Evil 7.
It could be implemented using configuration settings (Win/MacOS/Linux only) which allow specifying a command line (file path + arguments) per arcade machine, overriding their default game (or its broken state).
When such arcade machine gets activated it would show a black arcade machine screen, pauses the game and starts the external process. When TWP detects the termination of the started process it automatically unpauses and returns you to the arcade room (or when the user manually unpauses TWP).