Despite having issued the least number of Executive Orders in 120 years, Obama was excoriated for having usurped powers in an unconstitutional manner. Now it is easy for Congress to nullify any Executive Order by passing a law. It was Congress' failure to bring up laws, for a vote, that lead a frustrated Obama to issue his controversial Orders to begin with.
Again, although a new Congress was in session before Trump was sworn in, and Republicans had a majority in both Houses of Congress, they took no steps to change any of Obama's Executive Orders. They waited until Trump was sworn in, in what appears to be a permanent ceding of Congressional powers to the Executive Branch, to issue Executive Orders. So much for criticisms of Obama's unconstitutional behavior.