I've never seen a primal armor blueprint (or saddle etc) Only the standard ones

Could they be added to the drops?

Are you talking about Prime armors? The unbreakable armors? Blueprints are pointless as they can only be worn when you already know the tekgrams, and knowing the tekgram is the only way you can learn the blueprint.

Quality is a different story though, but ultimately, even the best quality armor won't really save you from getting one shotted by most threats.

To unlock Prime Armors, kill alpha tribesmen, now you can craft the armors in workbench and also wear them, or get sets from killing chieftains.

Prime Tek is unlocked from killing tek creatures and crafted in tek originator.

Supreme unlocks from killing a supreme creature and can be crafted in a supremes inventory when you got one.

At the beginning of EC the mod had Prime Armor blueprints with quality, and no tekgrams to learn before to wear it, but that's a long time ago...

Upgrade might be possible by using the upgrade Bench mod, no idea if you can add blueprints (with quality) to supply drops and i won't recommend reworking drops, but if you wanrt to try, maybe use engram unlocker mods or something like that so you can wear it. And upgrade bench might be funny, but all this destroys the whole balancing... your decision :-)