I think you are spot on that you he developed compensatory patterns that have allowed excessive scapula movement. Take it from someone who has had this surgery 3 times and rehabbed hundreds of shoulders. You do not have to live with this but it will take a lot of work. What you need is not just RTC strengthening but scapula stabilization alone and with all your strengthening exercises. Form should be emphasized and CKC exercises should be done. Any good therapist can provide these for you and work with you on this. If you don't correct this it will most likely get irritated again. Think of it like the fad term"core stability". If you stabilize the proximal(scapula) the distal will function as it should. They work together. We could go on for some time to explain the whats and whys but that isnt necessary here.