Steve,
I was in a similar situation. Shoulders not quite as bad, but have rotator problems w/both.
I do not want to revisit the six weeks of rehab for a "bum cuff", so I too was hesitant.
Dave at Wyvern walked me through every step of selection and purchase of a fabulous package.
I do a lot of rifle shooting, so the crossbow w/scope was just a rifle w/an odd form of kick. Same sight picture and trigger control. Also, takes about as long to recock and nock as it does to speed load a muzzle loader!!
The big difference is in cocking. I'm using a rope cocker w/no problem in the shoulders - and this required 100lb of force. NOTE: if you are short of stature (as I am), you have to pull higher on your body... your hands may reach your upper chest level at cocking - this can put extra pressure on the shoulder. Otherwise, I've been shooting 8-10 arrows several times a week without problem - but then, I don't push it either.
BTW, I'm shooting an Excal Vortex w/Hawke scope and am amazed by its (more than my) accuracy.
Hope you find something that works for you!!
Mike