Even though i dont like the pace of this episode, but Im not sure why would people expect any kind of character development from that flashback? It is obvious to me that they want to mimic the same situation when they were bully by big kids and Eren will always try to fight when Mikasamtry to help, similar to what happen in this fight, end up with Eren has run ( taken ) away and show how Mikasa actually feel. It is all about emotion and thats all. U dont need big Titan fight, or big revelation, or big plot/story move in every episode. And I know that people feel a bit rush when there are not many episodes left in this season. Manga reader should already know where they are going to end the season ( which i personally think it is perfect ).
And all Mikasa one directional character complain, you must be really new to anime or even japanese culture. Surprisingly character like this is very popular among the japanese reader/audience. Ayanami Rei from Evangelion is one good example.