>>87434761Amon had presence. He was intimidating, and a legitimate threat to Korra and the gang. The only other villains who can compare are the Red Lotus from season 3 (who I personally felt were alright but were never as interesting as Amon).
Now, I'll admit, that some of Amon's appeal did come from his mystery, and that was ruined by the reveal in the final two episodes of the first season, but I'll still go to bat and say he was a good villain. Even without his backstory, he was interesting because his goal was not to take over the world or plunge it into darkness; he simply wanted to level the playing field for everyone. It helped that the Equalisits were legitimately correct in a lot of their gripes (even though it was never mentioned again after season 1), so it seemed like Amon's goals were at least somewhat justifiable. You know, atl east until the reveal anyway. Plus, he a cool mask. Points for that.
>>87434827Both season 4 and season 1 had stupid endings. Amon gets beat because Korra magically learns airbending and Amon stupidly shows himself as a waterbender for no reason... And Kuvira, yeah, you got her covered.
Still, I'd say Amon was much better than Unalaq and Kuvira. Unalaq was never really threatening and his motive was basically evil for the sake of evil, and Kuvira was even worse. Not only was she evil for evils sake (setting up concentration camps and whatnot) she wasn't even a good bender like Unalaq could claim to be. She only barely defeated Korra because she had PTSD, and in the end she only got as far as she did because she somehow managed to build a giant robot in an ending that rivaled season 2's for stupidity.
I really didn't like season 4. Season 2 was an awful train-wreck, but there was entertainment to be had in it. Season 4 felt like a slog through and through even if it was functionally less bad.