The Quaint Cthulhu

Amon claims to be able to take away people's bending. A character (Tenzin I think) mentioned that only the Avatar can use this ability. So that got me thinking, what if Amon doesn't take away bending at all? Is he is just doing some kind of fancy chi blocking? It would make sense, the Spirits would never give ANYONE that power (with the exception of the Avatar). If he is doing this, (fancy chi blocking) then the results would be temporary.
So the question arises: wouldn't his "ability" be proven wrong already? Well, the victims of this "ability" are just beyond scared of Amon to even prove this "ability" wrong. They are probably scared what Amon and the Equalists would do to them and their family, or Amon threatened them and told them not to tell anyone that this "ability" is false.

People also theorize that Amon is not just taking away bending, but he absorbs that person's bending also. The final battle between Korra and Amon would basically be an Avatar battle. (Which would be awesome!)

And by far my favorite: people theorize that Amon is the second Avatar of this time. Do you remember the climax of Book 2: Earth (the original series)? If you don't here it is: Aang got struck by lightning by Azula, and he "died." Katara then healed him back to life with some sacred water. So what if in that time Aang was "dead" it was considered the death of a Avatar, and a new Avatar was born? In this theory, Amon is this accidental Avatar. That would make him about 73 years old, but this wouldn't be the first time someone this old in the Avatar series would have such physical ability. (Take Bumi and Lin Beifong for example.) But how did he get the ability to take away bending? Maybe he met the Lion Turtle and learned the same way Aang did, but there are so many more possibilities. So again, the final battle between Korra and Amon would be epic.

But this is all just people theorizing.