xkalybr
The Sword of Power!
Superman does everything at a super human level. All his powers are great. Simply take each of his powers away and see how he would function.
X-ray eyes, heat vision, and cold breath are great to have, but he could still be Superman without them.
Super speed, to include speed flight, is a key ability. Without it, it makes him not have the ability to fight crime half way around the planet at a moments notice. He would stay in Metropolis more often, like Batman is with Gotham.
His super intelligence is impressive, but that innocent boy scout mentality holds him back, which is why villains like Lex Luthor, and even Batman will always out think and out strategize him.
Super strength and durability. This power is practically 2nd to none to other heroes.
Superman takes so much more beatings than he should because he has no fight skills, and simply figures those punches he takes won't hurt him so bad. I mean, he is so fast, you figure he would never get hit, but he does, always. His strength saves him always, plus the fact that most villains can't hurt him.
If Superman lost his strength and durability, and kept the rest of his powers, he would nowhere be as great a hero. He'd get beat a lot more.
I'd say his Class 100 strength and durability is his most impressive attribute.
Let me add, imagine if Superman, at full power, learned some fight techniques, he would truly be unstoppable vs the really strong baddies. Maybe Batman showed him some pressure points, nerve hits, and how to evade punches. 😄