By not trying to clamp down hard on the edge cases of balance, Bethesda actually allows a greater variety of choice and play style, which is GOOD game design.
I think among the places we disagree, this is the most fundamental. You characterise this sort of thing as an edge case of balance; I believe that sometimes these problems go beyond that and would be more accurately described as exploits for the same reason that levelling sneak by sneak attacking the immortal tutorial NPC or speech via the bugged dialogue on an NPC in Riften are exploits. I believe that these represent
unintended interactions of game mechanics.
This is largely simple opinion: without an explicit statement from a developer to confirm or deny there is no way to know for sure where they stand on such things. However I believe their treatment of the stacking Alchemy effects in Oblivion is the relevant precedent and in that case it was treated exactly as I have suggested - as an exploit to be patched.
For me, it really boils down to this: if any given "exploit", "balance edge case" or what-have-you is genuinely an intended scenario, where are the NPCs in the world who are doing it. If there aren't
any then it probably isn't something that's supposed to be there. The player is unique in being Dragonborn but is far from the only powerful mage/experienced smith/whatever. If you seem to be the very first to have discovered some new technique to rise to power then there either needs to be an in-game explanation for why everybody else isn't doing it, or it simply shouldn't be there.
I'm not convinced, incidentally, that this conjuration thing is so severe that it falls into this category; it's not really very different from e.g. spamming Muffle to raise Illusion in my opinion. My argument is really with this tendency to go straight to "you're doing it wrong" and completely overlook the possibility that something might in fact need to be fixed. Balance has always been important in single player games and that this is a large complex sandbox world does not make it an exception.