I think that pigeonpigeon and Zaisha are digging into what might be the question behind the OP's questions: how much 'realism' do you like in your 'fantasy' story? Especially if that story's main purpose is to provide context for a 4X TBS game.
At base, the fantasy genre is infinitely flexible--that's why it can yield subgenres like steampunk and extremely esoteric things like Samuel R. Delany's stories set in Nevèrÿon (which I still can't pronounce despite loving the stuff utterly).
As an old hand at watching (and nagging) Stardock game devs, it seems to me that this might actually be an area to consider seriously as part of game-start options. In GC2, we have a research speed option and we still have a few folks who find the lowest setting too fast and resort to mods to get the 'galactic' feel they want--the gameplay detail is clearly important. Maybe Elemental can be the project where Stardock devs figure out how to do a parallel sort of option for tech complexity. That way, folks who liked to spend hours reading about medieval armor construction can play the game in ways they like while folks whose primary concern about armor is how it looks can play a slightly different form of the game and be equally satisfied. And of course, plenty of folks seem to like the middle ground of whatever 'pair of opposites' might be at hand.