This is just wishful thinking, but I would love a new class of watched words that allowed you to write a custom text for each word to pop up over the preview box in the same style as the automatic “Your topic is similar to…” and similar notifications.
That would explain why usage of a word is discouraged right there when the user tries to type it. And I’m sure people could come up with other uses for it as well, pointing users in the right direction when they try to type certain things 