Good points made, but there are a shitton of legal issues in other countries around the world, too. This is why the current exchanges are only open to a small number of countries. It is impossible to make it fit every jurisdiction in the world. Some problems include taxation, money laundering and money transmission... and this is not even the tip of the iceberg. It is like blocktrades said... If it was that easy, we would already have hundreds of those exchanges in the cryptospace.