I don't know how they can justify calling this Korra's book, when Jinora, Asami, random hoes that didn't exist in the show, granny versions of past characters and Pemma all have more consistent content than Korra does.
Honestly, I agree BUT I blame the show-writers rather than Mity for this. I'm a big fan of the original show and all the characters were incredibly fleshed out with great motivations, flashbacks, idiosyncrasies and everything that makes a character interesting. All Mity had to do was stick a "slutty" tag on the character and call it a day. Easy enough to do if you love the show which I'm quite sure they did.
Korra on the other hand, was written pretty badly. Where the other characters got what was effectively a novel's worth of characterization, she got the equivalent of half a sticky note. So, I think Mity decided to spread out the characterization from just Korra in order to make the job much easier for themselves. No complaining here, I love Jinora, though I do wish Korra hadn't gotten shafted in LoK too.