I'm excited for the AC movies but I do hope they don't decide to stuff it all in a 2.5 hour movie just to please/attract a larger crowd. AC's storyline is too complicated for that, they'd have to crop out a ton of things. And that's a big nono.
I had a feeling that they were going to do AC based movies for a while, a couple of months ago Ubisoft had posted a survey on their site with questions about your opinion on video-game based movies and how interested we were in movies based on AC, and if yes, which one (Alta?r or Ezio).
I hope it will be similar to Lineage, that one was perfect.