Can Aang be a powerful superhero in the Marvel universe?
Aang has mastered all the main elements and the elements that he is familiar with, he is a master of earth, water, fire, and air binding at the age of 66 years old (chronologically 166 years old), he also knows blood bending, metal bending, and the only avatar to learn energy bending (other than Korra, the Avatar after Aang). While he may not have shown the ability to use metal and blood bending, he should technically know how to use it very well, due to his mastery of the four main elements.
The capabilities of energybending are not well understood; what is known is that bending a person's life energy can impart them with knowledge instantly, remove their bending completely, or restore it. This bending art can be perilous to the user,
which is why so few have ever used it. In addition, even though mastering the four elements is a necessity for the Avatar, learning energybending is optional.
The known uses for energy bending are Astral Projection, Granting Bending, Removing Bending, and Spirit energy manipulation.
I have some theories of what Energy bending could do, with enough training and concentration, I think the bender could control, redirect, create, absorb, and manipulate energy, meaning Aang could absorb a light blast from Sentry, and absorb the gamma radiation from World Breaker Hulk so he won't be effected by it, and he could create a virtually indestructible force field/shield around him.
And if he were to enter the Avatar State, he become significantly more powerful, his mastery of the elements and trhe elements he hasn't mastyered but has trained, become strong enough to rival a minor god basically (in his universe, obviously. Now I will admit, I liked the Last Airbender show, and this may definitely be overexaggerating but it's possibly.
If he were to be in the Marvel Universe, he would be one of the most powerful, durable (depends on his power level and what element he's bending, like Toph when she made armor using metal bending, he could bend vibranium), fighters (He's trained ever since he was a child and has mastered many martial arts and non martial arts fighting styles/techniques), and he is pretty smart for a human, as he's went face to face with some of the most powerful and smartest Avatars, who could level continents at the base power level, and has mentally/telepathically trained with them (the Avatar State).