Charming, witty, and with some actual clever commentary. It's wierd to think of it like that, but it was one of the few anime that season whose dialogue was intelligent enough to really hold my interest, and I don't mean intelligent as in supremely academical, I mean intelligent as in there weren't any moments I wanted to scrape my face off.
Really? I quite liked her. As a character I mean. A lot of people are just like that in reality, and she actually DOES change. The second to last episode pretty much sets THAT fact in stone. Kyosuke isn't really her tool either. He makes it pretty obvious that he's doing it because he feels it's his duty as her brother, and probably because he actually cares about her.
I think you're assessment is actually really unfair and totally off the mark. Kirino is a good heroine at the very least because she doesn't fall too easily into the standard anime heroine stereotypes- even tsundere. She's an asshole at first, but some people are just like that. Especially middle school girls. Add to that that there's evidence of more going on behind the scenes, and her whole thanking him thing, and I definitely don't think you can call her selfish, bratty, ungrateful and unchanging.
I'd take Kirino any day over the overly cliched and staid girls, or mindless husks that sit around in other anime.
So I guess, at the risk of sounding like Richard E. Grant in the player, this is real.