I will take a moment to give compliments where due, I really like the new post type and the separation between excerpt and body. Used it excellently in another tag wiki.
In order to test out a revisions theory that waffles confirmed anyway, I edited the tag wiki for [roguelikes] on Gaming. It was mostly intended as a dummy edit, as I don't have a full article to construct on it.
Now, I would like to revert it back to the original excerpt that calls for help.
The roguelikes tag has no wiki, would you like to help us create it?
However, formatting is explicitly forbidden from the excerpts (with good enough reason), so I can't manually enter it. The original state doesn't count as a revision so there is no capability to roll back to it. And I decided to give entering a blank excerpt a shot, but all that does is leave a blank excerpt.
Edge case, maybe? I don't know how often people will realize that they aren't quite complete in their tag wikis, or reset the call for aid on the excerpt. But it's something of a "nice" feature that could be looked into.