I've said it once, and I'll say it again: I really don't understand the point of these cross game costume collaborations. If I want to play a character dressed as Ezio, I'll play Assassin's Creed. If I'm playing Final Fantasy, I'd rather play characters dressed as, you know, FF characters. I don't think that's an unreasonable request.
Yes, yes. Japanes role-playing game Final Fantasy XIII-2 is getting downloadable costumes that include Mass Effect and Assassin's Creed outfits. If you didn't find the screenshots thrilling, here is the AC trailer...you might find thrilling.