I'm not sure why you find this objectionable. Everyone has good showings, and they can be good showings in different ways. Superman has good showings where he wins by being portrayed as more powerful than normal. At other times it is because his speed gets played up more than usual. And some times he seems about as powerful as normal, but he fights really smart. It is the same for Thor. Sometimes his best showings are based on him seeming really strong, or especially skillful. And sometimes it is the hammer. Here, to me, it seemed like Thor was no stronger than usual, or tougher (though still plenty of each), but Mjolnir was kicking serious ass. It is still all Thor. what does it matter?
Thor does use his powers effectively about as often as Superman who tends to fight like a brick just like Thor. You cherry picking one showing is your thing.