Point is during a recent survey of courses, this subject was NOT taught. And I really do need documentation.
Something is wrong is... well, covering both "I have a minor issue with my ear" as well as "I have big problem that isn't being out of air", and following it with a thumbs up signal clearly communicates "this is a significant problem and we need to go to the surface". Not sure why anything else would be necessary honestly.
I have a problem (standard signal)- "points to ear", clearly communicates an issue with an ear that is probably minor, but if it's major we thumb the dive.
I have a problem (standard signal) - "points to calf", clearly communicates a cramp and we try to deal with that but if it's worse/doesn't get better, we thumb the dive.
I have a problem (standard signal) - "gives the *stay* or *hold* signal", clearly communicates they have an issue but are trying to sort it out there by themselves, if it doesn't get better, we can thumb the dive.
I have a problem (standard signal) - "gives thumbs up", clearly communicates there is a problem that is serious enough that we're ending the dive (who cares what the problem is at that point, we can talk about it on the surface).
I'm not sure that trying to come up with a specific signal for every possible problem underwater that a recreational diver could encounter, and trying to teach all of those to OW students, is the right answer when the established signals that are already taught can be used for pretty much every scenario.
This really seems like "a solution looking for a problem", not the other way around to me.
If that isn't instinctive to someone in a class, where we teach them the signals and ensure they understand that anyone can thumb the dive at any time for any reason (which has literally been part of pretty much every course I've ever heard of or taken that involves being in the water, either directly in the materials or as conveyed by the instructor (on more advanced classes), then there has been a major failure in the training from the instructor or a complete lack of paying attention by the student.