1) I think traders should sell all gun / tool parts (which would help craftsmen) and no weapon better than orange. They should be very expensive but always available.
2) The random stock does not seem like a good thing (sometimes I have to visit four or five traders to get something - or not - and it's just boring for nothing). Traders have to be an expensive alternative to randomness, not being part of it.
I hope the developers will separate what we can find in loot (books, high level weapons, tools and armor, etc.) and what we can buy. Reduce what traders are offering but make their stock always available. If I can't find a workstation schematic, there should be one last solution: buy the workstation at a very high price. I mean, after a week of intensive research, yes, I'm willing to pay 30,000 for a forge or 50,000 for a crucible. And it's good for the economy : we need to spare money for those essential items.
And, as I said before, traders shouldn't sell schematics, but only articles. As a cook, I don't sell my recipes, but only cooked meals. I don't want my customers to cook at home.