Anyone remember Asheron's Call 2? .. no, of course not. They tried this. It didn't work.
Buying and selling goods takes time, is monotonous, and requires having goods worth buying and selling. It's why player economies in games are all focused around the "better items" and not rat fur #6billionand4. Even if every item is useful in some way, some will inevitably be less useful than others and will become the grey 'garbage' items, kind of unavoidable. Sure, even in wow you could sell your grey total crap items, but who would care or want to buy them? Also it's been shown that having too many valuable items makes them seem worthless and having no items at all, while possibly a break from the grindhouse games of yesteryear, will inevitably have issues keeping players interested (and isn't really what you were going for anyway). In short, I would love to see it happen but I just don't really see it working that well.