Yes, the president should have to abide by tougher ethics rules. However, someone in the position of being president should not need ethics rules to govern their behavior. If that higher level of ethics is not possible without rules, then tougher rules are necessary to make sure that the president adheres to the ethical standards set forth by previous presidents.
There are already tough ethics rules. Every person that becomes President is rich. Trump is not that much more wealthy than any of the people who have become President. If Clinton had won, no one would have said anything, and she is a multi millionaire as well. There should be rules for presidents, but there are already rules in place.
The GOP would say that President Obama ignored countless ethics rules over the past eight years. Furthermore, the president issued countless executive orders that many felt were unconstitutional. Senator Warren's criticism of the GOP over ethics is a lot like the pot calling the kettle black. Warren should have shown more concern over ethics earlier.
The GOP is not putting the country in danger by ignoring ethics rules. In fact, Elizabeth Warren claiming that such his nearly a canard and political posturing to advance whatever wacky agenda she is carrying. The last person to talk about ethics should be a Elizabeth Warren, who got into Harvard Law school under the guise of having native American heritage.