So occasionally someone will get up my butt asking for my take on the "Korrasami Evidence," & I'm usually too lazy to answer, but I think this video does a decent job. By that, I mean I think it sticks to the best points, & is relatively comprehensive. I wouldn't sign off on all of it--especially not the music--but it does go a long way towards answering the question.
I'm sure people will still try to explain away this list, as if going out of one's way to find an alternate explanation actually proves anything, especially now that we know that the writers were indeed dropping hints.... Oh well, at least now nobody can say that I haven't given an answer.
1. Eh. Not a great point.
2. This one is absolutely true, I noticed this even in the trailer, & Avatar Parallels also noticed it.
3,4. This is a pretty recurring theme in the end of Book 3 & throughout Book 4, Korra & Asami show a lot of favoritism towards each other, & Asami particularly is willing to drop everything she's doing to become Korra's caretaker. There's really no reason why it has to be her, it's not the fact that they're both women, as Korra & Asami both invited Bolin & Mako to stay with them during Book 1. These are by no means the only scenes either, she's also the one who stays with Korra on Air Temple Island (noteworthy especially because this is their free time, not simply a mission) & there are also some background scenes where Korra chooses to stick around Asami even when the cast is assembled.
5. I can't say I really paid enough attention to this whole reunion scene to have much of an opinion, but you have to admit that most of it focuses on those 2. Another example, Asami is the most upset by Korra's absence. Even Mako thought something was going on between them that wasn't immediately obvious.
6. Yeah, people get all mad when I bring this up & usually say something like, "THEY DIDN'T HAVE SEX, YOU PIG!" Which is not even the point, the point is that everything about this scene displays a level of intimacy (which does NOT ONLY refer to sex, people) that you wouldn't expect from "just good friends." On Asami's side, once again, she's willing to drop everything to stay with Korra & take care of her, & on Korra's side, she's comfortable enough around Asami to allow her to change her. The whole thing is incredibly suggestive, & you can certainly take that in a dirty context if you WANT to, the innuendos certainly do nothing to dispel that, but I mean more in terms of an overall romantic attraction, rather than just lust.
7-10. The bad thing about this part of the list is that it's all derived from the final scenes of Book 4, but other than that, they're all good points.