I think its a bit of the writers on other shows arent good at writing Kara/Supergirl but Im going to propose a couple of other reasons Kara didnt have long conversations with the other heroes. Because Melissa is the best actor in DCTV its kinda a catch 22. She was the one capable of having extensive scenes/conversation with herself, which consequently took a lot of her limited time. The other thing Ill propose is for her development on her show the person she needed to interact with most was the evil heartless version of herself so she could see what she could become if she continues on the path of pushing her humanity away. Kara said facing an evil version of herself sure puts things in perspective. I dont think she wouldve gotten that perspective interacting with other characters, a pep talk with Barry wouldnt had the same effect.
True.. and I liked what it did for Kara although I hope her takeaway is not that she should not be Kryptonian any more. She should accept both her heritages; she is bi-cultural.
But.. but... but... The story was still Oliver-centric with sizable servings of Barry. Or, Arrow and Flash, I should say. Even in that scene where Kara says she would rather die than let someone else get killed instead of her to save Felicity, the focus of most of that entire scene is on Felicity... and you have more of that when Oliver-x comes and tries to kill her while she is saving Kara with her ex.
And Overgirl: The story was more about Oliver trying to save Kara-X rather than Kara-X herself.
And am also sad we didn't get a backstory on why Kara decides to join the Nazis.
I did enjoy the crossover. Just wished for more for Kara because I watch only Supergirl and anyways, she is my favourite (Alex is second). But, I am happy to be back with the regular showing.
And I was happy to hear Melissa sing.