Its mean people get blind from seeing the reality when they saw one character show godly feat. But actually character in Naruto is not that tough, I mean their body. Look at Naruto in Gaiden get pierce by simple sword not Totsuka or Kusanagi just simple sword. Actually Shin can do more like slicing Naruto in half. He save because he got Kurama for healing.
If I want to go outside of Naruto verse, I take DB for example. Goku's body get a hole after Sorbet shot him with laser.
From all that. Godly power mean nothing when your body dont live up to your power. In Itachi case if he can train his speed to another level, he can easily take down Sasuke. He got great weapon to defeat Sasuke but lack in speed also sensing.