That's not the kind of thing Beth does though.
I get where you're going with this, but really, it is something they've done before.
Morrowind's expansions introduced equipment at various tiers, but to be fair, Morrowind had a lot more wiggle-room. It seriously went Low tier(Iron,Steel,Chitin) - LOLU GUYS svck - High Tier(Daedric, Ebony, Glass.)
So with Tribunal, they introduced Adamantium weapons for mid-tier, and some relics for High-end.
Solsthiem was even better, with Nordic Steel filling out Mid-tier, Stalhrim coming in for High tier, huntsman for Low tier.
Oblivion kind of danced by the issue, by just making all Amber/Madness scale. Probably one of their most shameful moments, though I really loved the design for all the Amber/Madness weapons, especially Madness Axe - Amber Sword.
By the looks over it, Dawnguard has a mid-tier weapon selection. To me, and I hope I'm wrong, it looks like the Silver-ish weapons shown in screenshots like http://www.g4tv.com/images/4664/screenshots-e3-2012-skyrim-dawnguard-screenshots/77807/ and http://www.g4tv.com/images/4664/screenshots-e3-2012-skyrim-dawnguard-screenshots/77799/ might actually be a remesh update of the Skyforge Steel weapons. Others think it may be Mithril, I just have a feeling this weapons suite isn't a high-end series, since Dragonbone takes care of that.