For now. You can bet your ass the moment the avatar dies, they will exert their will over the puny humans like they used to in the days before the first avatar dragged them back to the shithole they crawled out of. The spirits are invaders from another world. They have demonstrated their contempt for humans repeatenly, and they are not to be trusted.
Although this time bending is more widespread than it was when Wan's world was formed, so that might be what keeps a better balance (that and no influence from Vaatu, if he was the progenitor of that prior world as claimed).
Canon it might be, but it only was made so because the writers couldn't find a way to put Korra in the right. Let's not ignore how Kuvira was the one who stepped up and said "The prince is weak and refuses to protect the people!", and then worked to do something about it. The prince is a hedonistic shit who upon ascending to the throne declared the Earth Kingdom to be a republic and then ran off. The daughter of Toph, who had a claim to help, instead decided to go "screq the outsiders", and stayed the same little shit she was in her teenager years. She was the one who caused Toph to retire and the current chief troubles.
Prince Wu being the spoiled brat he is, and Suyin's refusal to step up, doesn't justify Kuvira making herself into a fascist tyrant. (And I'd argue she did that in part by trying to emulate Suyin's governing style, Suyin was a bit of an authoritarian herself under all that art and crafts stuff. The rest was from her abandonment issues making her the ultimate control freak). Korra
was in the right to oppose Kuvira based on Kuvira's own actions, not just in seizing power rather than accepting Wu as Earth King, but in the way she behaved while taking over the Earth Kingdom. Whatever faults we got in Book 4 from not fleshing Kuvira out more (the damn budget cut that forced the clip show into the rotation didn't help I'd bet), I feel the writers did the job in establishing Kuvira as completely unfit to wield power. They didn't need the comics to "prove" Korra was right.
And the retcon about the avatar being powered by a symbiote is shit.
Yeah, the Raava thing was kind of... unnecessary I'd say? Honestly I'd have it where "Raava" doesn't exist anymore, but instead merged herself with Wan to save him and give him the power to beat Vaatu, and in turn making him a hybrid being of spirit and mortal that led to the cycle of partial rebirth.