Well they have answerd it here:

...Yeah not as stright-forward nor helpfull as i thought, although they do say some intresting thing's (like theorys on jesus and other historical mystery's),  the plot seem's to be turning more and more into the matrix if not enought already. Also i thought they said the next assassins creed was during the French Revoloution? Now it's back to Japan? Possibly a "red herring" for a laugh by the producers