I agree with
@TehChron @Strypgia. I think you made the point you intended. Besides, it's good for Shinji to show that he's not ALWAYS a shrinking violet/doormat anymore. I felt a little bad for Tanaka, but I dont think Shinji was wrong to be sharp with her either.
And like I said, Asuka acted very much in character. Wrong or not, it's how she is, and how she deals with people while in her arrogant public persona.
If people think this Asuka is unnecessarily mean to anyone not named Shinji, Kaji, Hikari, Misato (and she is still rather sharp with her sometimes) or in this story, Rei, should see how she acts towards one particular classmate in the fanfic Evangelion Genocide. Said classmate has the 'audacity' to playfully tease Asuka about having a thing for Shinji. Asuka beats up the poor girl, and even AFTER she and Shinji actually get together, still hates and belittles her for that one incident. This continues almost to the end of the story (she does make amends eventually though). Granted, this is 'canon' Asuka, post episode 24, so, it's not exactly surprising.
But, that's not really relevant to the point. The point is, A&T Asuka is still Asuka. She's not perfect and can be quite petty and bratty still. But given that most of her interactions in the story are with people she likes and cares about, it becomes easy to forget how venomous she can be when faced with people she doesn't like. It may not be a likeable quality, but it's all part of who Asuka is (or at least, part of her public persona).