Assassins Creed... I love those games but I think I belong to the minority of actually liking the first game.
What annoyed me in AC2 and ACB was the lack of control during missions. In the first game, fair enough the tasks in all the cities were repetitive, but at least I had more control on how I will execute the actual missions.
In AC2 there were less control. For example in one mission Mario said something like "take some mercenaries and raise some hell!" To this Ezio agreed while I screamed at the screen NO, that's a terrible idea, I want to go sneaky stabby!! This was even more frustrating on ACB where they introduced 100% sync. Of course I want 100%, but I was given too many conditions; not to be seen, kill with hidden blade, in under 3 minutes, while sucking the hem of your robes and so on. I don't see them stopping that, but one can always hope...
I actually never understood how did the "animus" know, how exactly Ezio killed his targets? If it knew that, what did they need Desmond for?