I am sure hope somebody™ already thought of this. Feel free to advertise your project here.
P.S.: Image transcription:
Patrick from SpongeBob SquarePants gesturing to the left with open hands:
Somebody should take document type conversion from Pandoc and version control from Git
Patrick gesturing to the right in a pushing motion:
And build a frontend around it
Well like uzay said, basically just an office GUI that allows me to import/export into a lot of formats and automates document versioning away.