I have SO many thoughts about this series and I just have not had time, and still don't, to get into it all. Also, I doubt anyone cares that much.
BUT, you're definitely hitting on one of the things I genuinely dislike about his writing; what we 'in the know' call Reenactorisms. It's kind of a two-fold problem. The first part is WAY overemphasizing things they like in their personal reenactment kit, and the second part is emphasizing elements of history that they're getting wrong just because all re-enactors do it. In this case it's like.. everyone has an axe, and everyone recognizes the seax as a weapon of war. Neither of these things is true, but re-enactors have spouted it for so long that it's just part and parcel to how they view the period, which he's extrapolated into his fantasy world really clumsily.
Bernard Cornwell is guilty of this too, with his 'seaxes punch through mail and are THE go-to weapon in the shield-wall' - which also are both utterly false.
The other big thing I disliked about the series was that every fucking character 'strides' everywhere they go. Not a single character ever walks somewhere. She STRODE over to him. He STRODE over there. She came STRIDING over to them while they were STRIDING over there and then they all STRODE together. Once you see it, it's like hot fucking knives in your eyeballs.
I say all this while adamant that this trilogy is incredible and I absolutely love it.
Are you going to start Evan Winter's books anytime soon? I think you'll get a huge kick out of his world building.