You do put a lot of work in your suggestiosn, great 
However without the pics from the trailer as direct reference, it is harder to see or imagine what exactly the unhistorical issues are. (I am not asking you to also to this, it just would probably be easier than showing your suggestions in sketches 
)
From what I read it does seem like there are some inaccuracies in the state of the preview. The most obvious would be a wrong type of shield. Could you compare the “correct” one of the period to a one used?
I would like the game to be as accurate as possible, however I think devs do too (which it seems in your criticism, you doubt).
Now the question is IF there are historical inaccuracies- WHY? and I do believe that we see or will see each armor/attack upgrade visible on each unit/type.
So if the english for example get armor upgrades 1 ae early, I think its possible they will have a technology which fits a later age, visible on their model, an age early.
I generally am interested in historical accuracy of age games, but also curious as to why there are dispcrepancies (IF there are)