There are two arguments that you could use in favor of the Proclamation of 1763. First, you could say that this was a moral law. By issuing this proclamation, the British government was protecting the Native Americans from having their lands taken from them by rapacious settlers. This was a good thing for the government to do. Second, you could say that this law made good sense economically. The British government did not want to have to spend a lot of money putting soldiers out beyond the Appalachians to protect the settlers from Indians. Therefore, it made sense for the government to issue this proclamation.
The major argument against the proclamation is that it infringed on the rights of the American colonists. Many colonists believed they had the right to live on whatever “unoccupied” land they wanted. It was wrong of the British government to limit their freedom in this way.