Government by Executive Order rather than Congressional law-making does not work. Just as President Trump has used Executive Orders to reverse President Obama's Executive Orders, the next President will reverse President Trump's Executive Orders creating uncertainty in every area of American life. Congress needs to step up and do it's job.
The President's unwillingness to work with Congress to fix laws he believes need fixing violates his constitutional oath to "faithfully execute" the laws of the land. Unchallenged, the President would set a precedent that reduces Congress to an investigative body.