I think it would be a good idea to have a thread solely for suggestions.
Ill start it off, I guess. I think it would be a good idea to be able to change the color of the text.
In other writing applications, I usually use orange to make small embedded notes, and gray to mark potential changes to words I don't like. (like a less intrusive strikethrough)
I made a quick mock-up in photoshop to better demonstrate. https://i.imgur.com/FY2gdUX.png
(just ignore my garbage first draft)