In the game only humans should be able to trade, with dwarfs coming in later. Trade is a uniquely human thing to do on a massive scale and thus trade should be theirs alone for the time being.
When determining these principles it's a question of "finesse".
Elves use alchemy and magic to "trade", and Orcs attack and pillage.
The concept of "Orc Trader" is (and should be) an Oxymoron. Orcs wouln't trade with you, they'd just kill you and take your stuff
Not only this but Elves wouldn't be pawning off Unicorns as livestock.
The market should be where one can purchase caravans that go to and from various cities on the minimap automatically to trade goods, and to accrue gold.