The Equalist could at least be seen as getting the jump on them due to Korra never fighting someone who tries to go in for straight up hand to hand and strikes to lock down chi paths.
Even Mako lost to them, and Mako's a super genius.
It's not the mooks, but the "big bads:" middle aged water tribe uncle who sits around plotting with Satan in Skype calls, criminals who haven't had practice with their skills in 13 years and were subject to extreme conditions against their type, and some dancer who is captain of the guard in a city that is a utopia with no bad guys to apprehend and only there on ceremony.
We see what the Avatar State can do when you can tap into it at will with Aang and the past Avatars. I can agree that Korra losing to guys like Unalaq, Zaheer, and Kuvira is stupid and plot induced, but at the same time what else was she supposed to do? Win? Defeat them and then what? Resolve the issues they bring up or correct the path the world is heading towards with nuanced writing, character progression, and balance? Pfft, that would take effort!