I think there is some terminology confusion here... C rating with regard to Li batteries means the rate at which the battery can safely be discharged. C rating with regard to Nixx batteries means the capacity of the battery - how many mAh the battery holds. Unfortunately this hobby has used "C" for both parameters. Or am I mistaken?

At any rate, I have also noticed that the higher the energy density of a pack, the shorter the lifespan of the pack. For example, 1100 mAh NiCd AA cells last only 2 or 3 years while 700 mAh AA cells can last 10 years. This is one advantage of using sub C sized cells of the same capacity as AA sized cells. But the big advantage is the lower internal resistance of sub C cells and therefore their ability to source higher current.