The more I think of it, the more I realize that I'm just not impressed by Kuvira as the big bad.
She's given a lot of hype (Suyin basically describing her as a prodigy, Korra saying that things are more out of balance now than they have ever been), embodies what I honestly view as a relative lack of threat compared to the other villains (Amon and Zaheer seemed far more personally powerful and even Unalaq arguably has better feats), has been given a semi-infallible presentation thus far (curbs Korra, declares herself ruler of the Earth Kingdom while everyone else stupidly watches and lets her leave the city, everything coming according to her plans thus far), and rounds all this out with frankly sort of boring motivations. We see a flashback of Kuvira going into this with a desire to do good and basically save the Earth Kingdom, but as of right now her villainy is so unambiguously certain it's actually kind of corny. She gets laughably evil scenes (like the petty hostile takeover of Wu's suite, the concentration camps for undesirables, or whatever) that make me cringe. It isn't cool or chilling in its villainy. It's boring. I think the reason for this is that we never really saw any transition or change between what she set out to do and what she has become.