While a reasonable explanation, it kind of makes Unalaq come across as even more of a dick from my perspective, when it seems like the Northern Tribe should have been a lot more involved from the get-go if it was such a big deal.
We don't know how long ago he took over as chief. We only know that it was sometime later than 151 ASC (After Sozin's Comet), the year that Tonraq was banished, and sometime before the current year, 171 ASC. And we know the Southern Tribe had had all its benders save Katara wiped out before 94 ASC (the year Katara's mother was killed). So by the time Unalaq reached a position of leadership, the South's loss of spiritual connection would've been a fact of life for anywhere from 60-80 years. I don't see how he can be blamed for the policies of his predecessors in the chieftainship.
Well, but that's sort of been true with Legend of Korra a lot, blending what seems to us a lot more American-esque stylistic choices to show the advance of technology while never losing the obvious Asian-inspired origins. It just felt to me like a logical continuation of that trend, much like with the... guy... Asami was there to talk to in the first place.
I guess that's the problem... for pre-modern culture and technology, they can draw on purely Asian referents, but for modern technology, the only available historical precedents are either from the West or influenced by the West. So it's hard to keep a Western look from creeping in. Still, they did a good job with the Satomobiles, making them look like an Asian take on '20s cars (though I doubt they have very good aerodynamics).
While it's clear the Asian inspired cultures are the dominant ones, for all we know there's a relatively small group of highland dwelling earthbenders with a thing for playing the bagpipes and a taste for koala sheep stomach stuffed with wheat and barley.
Not impossible, I suppose. While the main populations are based on China (Earth), Japan (Fire), the Inuit (Water), and Tibet (Air), we've also seen Guru Pathik, who appeared Indian, and the Sun Warriors, who looked Mesoamerican. So there could conceivably be other ethnic types somewhere -- African, European, aboriginal Australian, etc. But we haven't seen any indication thereof.
I guess this makes sense if we're just thinking of the Avatar State as the Avatar powering up, it's just that throughout A:TLA - and especially at the end of Season 2 - it seemed to be extremely connected with the spiritual nature of the Avatar, and that controlling it/willing it was something that even Aang with his highly-developed spiritual nature had difficulty with.
Well, yes, but what I'm saying is that it was difficult for him because he was afraid of the power aspect of it. He could easily access the state because the spiritual came so easily to him, but the power frightened him and overwhelmed him. (The fact that he was a 12-year-old kid may have been a factor in his problems controlling it as well.) Korra needed a long time to reach the point where she was spiritually able to access the state, but once she figured that out, harnessing the power of it came naturally to her. She's forged the spiritual connection at last, and that's not going away now that the bond is there, so she can enter the state at will, and isn't as reluctant to do so as Aang was, so it comes even more easily to her. But she hasn't yet gained an understanding of what it
means to have that spiritual connection, and how to use it wisely.
Or it's just a minor retcon and I can stop thinking about The Guru, which is fine.
Well, let's see. Blocked chakras interfere with the Avatar State, and the chakras are blocked by fear, guilt, shame, grief, lies (to ourselves), illusion (of separation), and attachment. Korra's not prone to fear or shame, and is self-assured enough that she probably doesn't feel much guilt. I'm not sure she's got anyone to grieve. She's attached to Mako and her friends, but self-reliant enough that maybe it's not something she has a problem setting aside. Lies and illusion are the problems, though; she's often been less than honest with herself about her own fears and vulnerabilities.
Still, there are many paths to spirituality. Pathik's way of unblocking the chakras was one approach, but that doesn't mean it's the absolute rule that every Avatar must follow. And it was more an intensive therapy for remedying a problem Aang was having due to his emotional turmoil, rather than something he needed to start using the state in the first place. So it's not implausible that Korra could manage without it.