Can't really blame the authors, tbh. Nickelodeon made everything possible to fuck up the show, expecting them to allow any kind of advance on LGBTQ topics? lol. I find it believable because there were important signs, for example Korra opened up her heart only to her on her letters. And it's not as if they passionately kissed at the end, or say something like "i love you", they were starting something, holding hands, etc. They didn't jump from 0 to 100 as you are trying to tell.
They could definitely handled romance better but, i give them kudos for trying to break the mold, specially considering nickelodeon.
I blame the authors. Again, they were trying to have their cake and eat it too.
It wasn't like they had to do anything explicitly romantic, they only needed to have the characters spend time with each other, and deal with problems together. One of my favourite romances in films, and a fantastic example of how to build up emotionally toward a love confession, is Han Solo and Leia in The Empire Strikes Back. I've used this example before, but Korra and Asami getting together was like if the "I love you/I know" scene at the end of ESB hadn't been preceded by Han and Leia spending the whole film together. The emotional build-up doesn't come from Han and Leia doing romantic things with each other, it comes from them spending time together, working together, and trying to solve problems and escape the Empire together with Chewbacca and C3PO. You don't need anything expressly romantic to build up the relationship between two characters, just have them spend time with each other.
I thought stuff like in Book 3 with Korra being taught to drive did a pretty good job, and they allowed that to happen, so I don't see why Nick wouldn't have allowed similar stuff in Book 4. But the creators chose to have that ship
and split up all the characters, cutting off a lot of time that could have been used to build up the relationship. There were a lot of little things they could have done to build up the ship more, but they chose not to. Here are some suggestions I heard after the finale:
- Have Asami be the one searching for Korra near the spirit portal at the end, instead of Mako.
- Have Korra look more worried when Hiroshi is killed (for all she knows, Asami was in the Hummingbird with him).
Those are suggestions pertaining only the finale. There are a bunch of other ways the season could have been changed to make it work better. Again, they were trying to have their cake and eat it too. As it is, I think it didn't really make sense for Korra to end up with anyone at the end, since romance wasn't exactly a thing in the later seasons (I also thought it would be refreshing to not have a series where the lead has to hook up with someone).
If they wanted to make the Korrasami romance work, they should have changed the structure of the season. Not have Korra spend so much time on her own. Spend less time getting the main characters back together.
As it is though, it's a mess, like a lot of other aspects of the show.
Also you're kidding me, Korra/Asami have natural chemistry in spades, better than Korra or Asami ever had with Mako. Mako doesn't chemist with anybody. That ep in S3 where Asami and Korra just hang out is just great vibes. That said you're right, they barely interact much in S1 and S2 and that's almost solely because of the garbage Mako storyline.
Saying they have more chemistry than Korra and Mako is like saying Death Valley has more water than the surface of Mercury. Sure, it's true, but it isn't saying much.