After delving pretty deep into all the secret/side-content hidden on Abstergo computers, diaries, etc..... I'm pretty sure they're setting us up for China Creed. There's chronicled evidence of Ezio training a 'chinese girl' -- which, because it's written in canon perspective, could be any sort of asian really (there's been some talk about Japan too), but from a historical perspective there's a *lot* more upheaval in China that would be conducive to a Templar story arc.