Sure, I could do that. But I still want the woodcutting to be relevant so I don't want traders to sell too much wood, but if they sell too little, then they will be less useful.
My idea was to add a logging camp where you can order wood. The more wood you order, the longer you will have to wait before it is ready, which would balance things a bit.
But the Riverstone NPC could sell a little wood to you. I don't really see an issue with that.