Maybe I'm confusing Clever and Intelligence. Naruto is extremely clever I know that for a fact, but in terms of Intelligence maybe that's where we have our disagreements. I think most of us can I agree we loved Naruto because of his ability to be clever, use misdirection, layering basic skills, and using an enemy's assumption against them. That makes the battle interesting, fun, exciting, and still makes the last blow landed give the entire battle an uncertainty of who comes out on top. Best example is the fight during Zabuza or Neji.
When I speak of Intelligence, I meant his pre-battle mind being analytical. He doesn't do that very often and it annoys me when people have him stand back watching his allies fight while he himself stands back and does some thinking. Not very Naruto in the sense of mind or the sense of his loyalty to his allies, simply using them isn't his style.
I can understand a powerful Naruto. The NaruIno story "Foxhound" is the best example I've ever seen of strong/intelligent/advance!naruto. His powers slightly borrowed and then remixed with his own useful flairs gives it a distinct Naruto-vibe that seems canon, Intelligent but light hearted and not over-thinking. That's Naruto, and that's the sort of level I feel keeps the story very good. Challenging, unclear, and most of all fresh.
Most fanfiction stories take his powers far beyond, like killing Orochimaru or Itachi with a single punch and not having the enemy counter whatsoever. Intelligence that has him out think Shikamaru or Zetsu which are extremely intelligent fighters. Thinking thousands of steps ahead, but not well written.