BY moderate sized axe I meant something along the lines of a GB SFA. I have certainly struggled with huge logs with similar sized axe, but I suppose mainly when the wood is a bit knotted which is probably where the problem lies. I ended up buying a log greade to pount with a sledghammer for the huge/knotted bits.On the first point: I normally split several cords of firewood every year from logs bigger than that as a teenager. So NO, it's not much of a job at all for an axe; just another everyday job. It is way too much to expect of a knife though.
Second point: Neithet do I and I also expect to do a "reasonabl" amount of prying (especially when digging roots) with a knife. However, if you're really expecting to do a lot of heavier prying with it, you might want to get a blunt tipped, heavy bladed, diver's knife instead.
With regards to point 2: I am merely trying to acertain what may or may not weaken a bushcraft/survival knife. I don't think I would ever intend on going out and prying open something, but would like to know that if I had to that a design feature of the knife is not going to make it more likely to break on resulting in probable injury, and lack of knife. DOes that make sense?