Really? Season 3 was my favourite, especially the villian. He's got a clear ideology which happens to be at odds with Korra; I don't agree with his ideology or the methods he uses, but he's definitely understandable.
For Korra, they purposely set up all the villians different to ATLA; Aang mostly had his head screwed on straight, but was passive and didn't like confrontation, ergo the best villians to have as a counterpoint were those who challenged him physically.
Korra is much different from Aang - raised in peaceful times (pro bending is a sport, not a combat style ), hyper confident and well trained, she's aggressive and very physical. In this case, more physically powerful villians wouldn't be interesting as it would just be re-hash of DBZ with them powering up at each other, so most of her villians challenge her ideology and beliefs.
As an example, Amon had a point - organised crime benders were busy terrorising the civilians, so helping them form self defence leagues (or militias by another name) is a perfectly reasonable response.
I agree with this - black humour has a long tradition, especially in the military, where death, pain and suffering is omnipresent. The spartans were famous for this, from 'that's nice, we'll fight in the shade' to 'If'.