An idea can be more interesting than a person. Sadly.
I think Amon as a water bender could have been more interesting if
he was the one who most believed his own lies.
What if, when Noatak left the South Pole, he gave up water bending entirely? No bloodbending to win fights, just physical training and sheer will.
What if Noatak was so angry at his own past, in a moment of insanity he convinced himself he was someone else?
What if Amon
did have the scar, but he gave it to himself because he wanted to believe he was a different person?
What if Amon didn't think of his power to take away other people's bending as a form of bending?
What if he locked up Tarrlok not because Tarrlok would tell other people who he was, but because he subconsciously didn't want to be reminded he was just a water bender?
What if the series finale wasn't Korra exposing him to the Equalists, but Korra exposing him to
himself?
I'd find that a lot more interesting than what we got. It'd make Amon a more complex character and would also make him more frightening because of his dedication.
That's the problem with Korra, it's hard not to write fanfiction what-ifs because you always end up disappointed by the direction it goes.