I kind of happened to see the first two books of LoK before I watched AtLA, so at first I liked Lin, like "Yes, I like this grumpy sarcastic badass lady", but then I watched the first series and saw "the original BeiFong" and that was it. I love the whole BeiFong family to be honest. And yeah, though Toph really wasn't the best mother, especially for Lin, I think that it's important, too. Because, like, there're a lot of people who aren't perfect in real life, in frank, nobody is, so it's only fair if someone as badass as Toph would have flaws in some area. And that seems to be family. At least she seems to accept that she wasn't right in the end, and her daughters still turned out to be beautiful women, so.
Also I nearly cried about that "Can friendships last more then one lifetime" thing when Toph called Korra "twinkle-toes".