Damn straight, it's rare for a secondary character to get their own show and a tsundere one too. Now if only other shows would follow suit: how about a spin-off anime for Tohsaka (FSN) or Kyou from Clannad?
I've been jobless and job hunting for more than 6 hours a day will turn your brain to goo, so I've been tanking series that I missed. Index being one of them. And yeah, it was absolutely excellent. I loved it's "arc" structure and it had no stories I disliked. I'm really glad Mikoto is getting her own show. I really liked her.