Valid points.
Well, I don't plan to be too far out in the wilderness on my own, so I will either have a buddy as a passenger, or most likely be with at least one other 4x4. The spare wheels/tires combo will be a last resort option. I will have plugs and a C02 compressor with me which will hopefully take care of most tire issues without fubaring my back.
I'm actually considering changing my rear setup to this because I don't think I really need two spares, and even if I wanted two I could keep one spare where it is from the factory and add the second to the rack.
The advantage of this is that I can actually fit the decked system under the tire mount for better organization, the disadvantage is that I won't have dedicated slots for all the water/gas jugs, C02 tank, and jack ... and I'm not sure how I could organize and secure all that on top of the decked platform.