Sawa-chan may be acting more mature, inside she's still the attention-craving Sawako we saw in the first season. Evidenced by Yui and Ritsu both telling her she once again overdid it. Hilarious scene.
Between the last two episodes of the first season and the first 3 episodes of this season, Ritsu has all but displaced Yui as my favorite in the group. They really gave her a lot more depth and personality. I loved seeing her with the side ponytail too, it's an interesting look for her.
Three episodes in and this season is already far and away better than almost the entire first season of the show. 9/10 episode for me, and I look forward to Mugi's new song.
Edit: I could totally see HTT covering Remedy. I could also see this, even though there's no keyboard involved:
http://www.youtube.com/watch?v=oh8zcbC_Dcw (Story of My Life by Social Distortion)
It'd fit with one of the underlying themes for this season too, I think. Maybe Mugi could do backup vocals for it instead?