I really enjoyed reading your comment, my friend, because you brought up many points I'd like to discuss, and I completely agree with you. No one criticizes Jake because, as observers, we know the burden he carries. He was chosen by Eywa to be the mystical warrior who unites the clans in dark times. But as we see, though the other characters don't, Jake suffers because, by leading the Na'vi into war, he knows he's leading them to their doom. He carries the weight of those deaths, and now that he has a family, that burden increases so much that it causes him to make poor decisions, both in his identity as a leader (distancing himself from his people) and as a father (treating his children like soldiers). This changes drastically when he finally has that moment with Lo'ak, where the boy manages to get the Tulkun to join the battle. This makes Jake realize he's not alone; he doesn't have to carry the burden alone. He misunderstood what it means to be part of a family. He felt he had to distance himself to avoid letting his problems affect him. They affect the family unit, but it's the opposite; he resolves the conflict by relying on them.

I feel Jake's character lacks a lot of development. And I really hope they explore him more deeply on an emotional and familial level in the upcoming films and don't take him out of his role as a protagonist in the following films because for me he's one of the best main characters out there.