Please kindly read the entire thread before deciding to post.
And take note of this post which has links to YouTube support. Follow those links and read.
1. It's already been tried. (Again, read the thread, all of it, before posting.)
2. The built-in SSUAO was specifically chosen to make youtube videos work in Pale Moon. Pretending to be, for example, Chrome will have negative consequences since it will falsely advertise the browser's feature set.