Are there any unlockables in Assassin's Creed Revelations from playing the prior games?
Solution 1:
Yes. If you've played AC:B multiplayer that unlocks the Courtesan for use in Revelations multiplayer.
That's it though.
Solution 2:
Now that I've finally had a chance to sit down and play this - no. I have full completion on all the other games, and started this one essentially naked.