@putty Your time to shine or @davidkingham if still interested. 
I’ve something that works.
url: https://github.com/Arkshine/discourse-video-upload
branch: modernize
Features-wise, more or less the same with:
- A slightly refreshed interface
- Resumable upload support (default chunksize is 64M)
- Modal can’t be closed when uploading unless you pause
- Google API is now loaded only when Auth is necessary
Let me know if it works well!
There are probably edge cases I did not expect.