I'd love to be able to add , save, or export sheets from my games into external files, to study them from Notepad, VI, or whatever editor I wish. Of course, this idea is focused on game's logic code (the event sheets from Construct) as they are they define a game's design ideas.
I also believe this would eventually lead other people to make code converters between some known file formats. (for example, from MMF to CAP).
I'm conceiving the bases for a High Level, Readable, text file format, based on XML, as it's the best suited for this proposal.