The thing is - there would not be a one-size-fit-all exercise for each muscle group; you would rather need an exercise for each combination of A, B in "muscle A is weak but surrounding muscle B is strong"
I'm not sure if the B dimension affects exercise choice. If it does, it could be covered by providing a short list of exercises to try for activating each muscle group A. That way the user doesn't have to figure out which muscle(s) B are compensating, which could be challenging for a lot of people who need this information. In my case, I'm still not sure exactly how my body was compensating for the muscles in my back that weren't being utilized.
I think that there are fewer likely culprits than you might think. Most lifting coaches end up heavily relying on only a few cues per exercise, because there aren't that many common pathologies. So something like this could be useful if couched in the normal "not medical advice" sort of way. Yeah, this might not apply to you, but if you find that you e.g. squat with too much forward lean, here is a small set of exercises to augment your workout that you should try for 6 weeks and see if it helps.
Something like that would seem useful to a lot of lower-mid weightlifters who don't have a real lifting coach.
