I don't think that we need another set of law besides the law of the country we live in. Especially laws that directly contradicts with principles of the nation in question or a law that oppressed the other people of a different religion. Besides, i think that a good country is secular country, not a country that run by religious fanatics
Shariah Courts are not ethical, in the sense that they oppose religious law on people who are not voluntarily choosing to follow it. However if these courts were only subjecting people who had voluntarily decided to submit to these laws, then their is no reason why they cannot be a part of that person's belief system.
No, Shariah Courts should not be banned in the United States. The U.S. was founded on the principal of religious liberty. While not everyone will agree with different religious practices, it is important for the government not to interfere unless a particular religion is leading to crimes against humanity. Otherwise, it must be legal.
Sharia courts are commonplace in middle eastern countries where sharia law is a significant part of the countries' governments. In culturally diverse places such as the United States, religious law has no place in the government. Countries that revolve around Islam, however, have a right to enforce their religious law because their religion and government are intertwined.
No, I do not feel that Shariah courts should be banned. However, they likely need a major overhaul. It is prudent to have checks and balances in place. All courts, including Shariah courts, need to be fair and just. A qualified party should take a close look and determine where these courts can be improved.