A pressure suit, by itself, might absorb some of the impact to your shoulder by dispersing it over a slightly larger area of your shoulder and upper arm than a shoulder pad inside a jacket. That's only a guess, of course. Depending on how a person falls, the chest and spinal protectors might also absorb some impact. Like others have said, nearly identical crashes can result in different injuries (or non-injuries), one never knows until you try it.
The airbag vest I wear has inflatable portions that cover the lateral ribcage and it's possible that could make a significant difference in an event like yours. Also, my Knox chest protector wraps around my chest to about the lateral midline, rather than just covering the front of the chest, as some do. Likewise, some pressure suits cover the thorax more completely than others.
My airbag inflated when I was flicked off my bike in a very slow speed tip over, so I don't see why it wouldn't do the same in a typical higher velocity low-side, high-side, rear-end collision, frontal strike or most other scenarios involving significant force that would detach a rider from a bike. Would it inflate before impact? I don't know but it's rated to fully inflate 0.2 seconds after being triggered.
In regard to hot weather, I've worn all the gear that I described up to 95 degree temps in relatively high humidity, with a vented jacket and pants. I'm relatively heat tolerant, though. Above that temperature, or riding on challenging trails, I might want to shed some of the gear or wait for cooler temps.
Also, as someone already suggested, you might talk with your doctor about osteopenia/osteoporosis. Smoking, drinking much alcohol, routinely drinking many soft drinks, etc, can make a person more prone toward having brittle bones. Bone density can be measured fairly easily.