Here's another thought about if there were to be changes to the series. Of course, even some of the plots create inter-team conflict, which are good ways of testing character developments. You all know how Mako and Korra broke up in Book 2. I feel that was too small an approach. I feel what they should have done is added more episodes to the season, and expanded the conflict between Mako and Korra a little. How about Mako breaks up with Korra, AND quits Team Avatar. I'd say dial down the issues between Mako and Bolin and make it so that Team Avatar splits in two--with Mako leading his team with Bolin, and Korra leading her team with Asami. The idea behind this is that Mako questions Korra's leadership of Team Avatar because she can't see past her personal feelings (that has been the governing issue in Book 2). As a result, Mako can't stand by a leader who won't listen to others.
From what I've seen, Team Avatar looked TOO well oiled, and that makes Team Avatar look TOO perfect. It just doesn't seem like good writing without testing their team dynamics. A lot of superteams have gone through experiences where they split up over disagreement with a particular crisis, it becomes a major plot point, then they learn to appreciate their differences and reassemble. It happened with the Avengers in "Avengers Disassebled" storyline, as well as the "Civil War" storyline and some cases with DC's Justice League as well. Part of being a well-defined team means appreciating each others' differences, and that's the lesson that "Team Breakup plots" tend to give out.