While Shanks' combat skills are seen very sparingly throughout One Piece, there's little to no doubt he's stronger than Luffy and could defeat the Supernova.
Shanks is one of the Four Emperors of the Sea and certainly the strongest in their ranks right now. He possesses a bounty of over 4 billion berries right now, which is certainly the highest active pirate bounty that the fans know of. Shanks does not possess any Devil Fruit power, unlike Luffy.
While using Gear 5th, Luffy is able to extend his elasticity to inanimate objects. Luffy's devil fruit awakening allowed him to beat Kaido, who was considered the "Strongest Creature in the World." In his Gear 5th form, there are not many One Piece characters who can defeat him.
It depends on how quick the fight will last. Luffy's Gears are costly and can't be maintained for long stretches of time and neither can Baryon Mode for Naruto. Due to the number of drawbacks the Baryon Mode brings, Luffy will probably clinch victory in Naruto vs. Luffy if they break those modes out.
However, physical blows without Haki don't work on him due to his rubber body, and the only slashing-style ninjutsu Sakura is shown to know is a scalpel-like blade. With that being her only weapon to hurt Luffy with, it's likely she will lose this fight in embarrassing fashion.
Conis and the rest of Skypiea witnessed Luffy completely destabilize Enel's attack. She then witnessed Luffy finally defeat Enel by punching the god straight into the golden bell.
It is evident that the only person capable of surpassing Roger is Luffy. Even though Luffy still has a lot to achieve, he is the only person who can transform the entire world.
Goku is one of the strongest characters not just in Dragon Ball, but within the entire anime world. Luffy's biggest mistake would be to get on the wrong side of Goku. There isn't any competition and even if Luffy got over a hundred attempts to beat Goku, he would still be unsuccessful.
Eclipsing Zoro in both mastery of Armament and Conqueror's Haki, Luffy proves himself stronger than Zoro overall. While Zoro does edge out a victory in terms of strength and physical endurance, Armament and Conqueror's Haki are undoubtedly the two more relevant factors here.
Anime is full of strong characters, but some - like Goku, All Might, and Luffy - stand out as some of the most powerful anime characters. Ninjas, mutants, demons, cyborgs, and aliens battle across anime with sword strokes powerful enough to slice through steel and energy blasts that can level mountains.
Luffy fought several enemies. Yes, he triumphed many times, but at other times, he suffered humiliating defeats. Here are 5 Times Luffy emerged victoriously, and 5 times he suffered a bitter defeat.
Dracule Mihawk is Zoro's biggest rival, being the man who holds the title of the World's Strongest Swordsman. Mihawk is extremely skilled with the blade and his swordplay is described as very aesthetic. He is also extremely good at using Haki given that he taught its usage to Zoro.
Unfortunately, Luffy's rubber body doesn't make him impervious to fire, so Sasuke is already stronger thanks to his Amaterasu, and his Susanoo's arrows are strong enough to pierce Luffy's body.
Mortician: Sasuke was also way faster, Zoro was fast enough to keep with the teleporting Former King of Sorbet Bartholomew Kuma.
Luffy is one of the strongest One Piece characters, but he likely can't defeat the entire Narutoverse by himself.
Fan theory suggests that Luffy will awaken Gear 6 in One Piece. The concept of Gears was introduced in the Enies Lobby arc of One Piece when Luffy brought out Gear 2 against the CP9 agent Blueno. His skin turned pinkish and heated up, allowing our main character to move faster.
While Luffy's Gear Fifth abilities are indeed impressive, they are not equal to Son Goku's mastery. Gear Fifth is an interesting fighting technique that has been used very effectively in combat thus far, but not against super beings like Goku.
So yes,Luffy can take the Admirals as well as Smoker. I think that we can only wait and see how he does against a Logia user, as he is soon to fight Ceasar Clown.