If you ever plan on diving from a small boat where you need to dump your tanks in the water before you haul your butt into the boat, a QR shoulder release is mandatory in my opinion. The number times I've had divers damn near drown a foot from my boat as they struggle with their arms pinned behind them. On two occassions, I had to take my shears to the shoulder strap or they would have. I was careful to cut in just the right spot to install a buckle later on.
I know there's a whole school that considers a potential failure spot... but krickies, everything is. Personally, I"m a lot more concerned about my drysuit zipper failing, and about 16 other things. Having said that, but a solid metal buckle on or a delrin squeezy thing in. (I don't prefer those here as they're hard to work with cold-paralyzed fingers.