Personally, aside from can light or long hose, part of the reason I like the simple DSS rig is the streamlined efficiency. Because of that, I don't see a reason to hang a bunch of things off the rig, and thus don't see a reason for more D-rings. My personal preference for storing things is a pocket, since it's more streamlined.
But if you prefer putting it there, with no long hose or can light, I see no reason why not. But please consider a pocket may be a better place - even for recreational diving.
But if you prefer putting it there, with no long hose or can light, I see no reason why not. But please consider a pocket may be a better place - even for recreational diving.