Tense and plurals is one that would that seems like it would be helpful for a computer to keep consistent while you edit, so when you edit the subject to be plural from singular, it tacks on the "s" onto the verb for you. If you had

"Families enjoy this restaurant"

And started typing and changed "Families" to "our family" this "photoshop for text" would change "enjoy" to "enjoys" for you.

Enough little facets like that, I could see being useful.