Expand Expy to cover characters who appear in other people's work who are not Captain Ersatzes. Wicks that misuse it for Captain Ersatz would need to be hunted down and fixed.

• This would be reverting it to its original meaning.

Make Expy the supertrope, and move the current idea of Expy to a new subtrope. Make Captain Ersatz a subtrope, as well.

• We may make the other trope described in the OP a subtrope as well.

Launch the third trope that covers the ground between the two and fix all the wicks (can I say ouch?). See if misuse continues at the same rate afterward.

• We would need to clean up Expy's description.