Was my comment that prompted this. The nice pale tan and blue is pleasant and works fine most of the time, but when someone only changes one or two characters it's essentially invisible on a white background, and I suspect many just move on to something else rather than trying to spot where a single comma may have been changed somewhere in an entire paragraph. If we could just make it change to a more visible color when an edit only effects one or two characters, it would be a small but occasionally very useful quality of life improvement.

I would also note that some kind of different highlight for potentially syntax breaking changes to sequences like '' ''' {{ }} [ [[ ]] ] would also be appreciated...

I appreciate full syntax highlighting isn't yet on the cards.