I was thinking that the way they could explore the renaiscance more is have DLC but not with ezio; but with his apprentice or partial apprentice Franceso Vecellio and his group of assassins. we could go a little further or back but still within Ezio's time. From what I've read of him, his story is very intresting and i would like it a lot if they created DLC for him but with a multiplayer for campaign so you need friends at times to help you. then they could have more multiplayer characters with his targets. you could also finish off some of the rest of the templar aganets Ezio didn't take care of.
I also think that with the French symbols appearing, Desmond needs to go to various cities around the world and sync with the assassin's that resided there to find where the temple is. Because usually Desmond's assassin ancestors were all master assassin's who knew where the temples were. We could also learn more about Desmond as he syncs with himself after completing an ancestor secquence. My idea is that we start with France and have 2-3 sequences with the France then have a personal memory experience with Desmond, leading up to the finding of the temple and exploring the modern city. Then we could go back further to the Mayans and aztecs for the same amount of secquences or less the nhead over there to rinse, wash, and repeat. next would be Russia but the twist in the gameplay would be that this ancestor is killed, You could feature Nikolai Orelov as a side character. Rinse, wash, repeat. Finally you go back to the states for a confrontation with Abstergo but not before synching with your great grandfather and the assassinations of Franz Ferdinand, Mussolini, Hitler, and Roosevelt. and then going to take the apple hidden within the white house and exploring a templar controlled DC. The last sequence shows us Desmonds final memories before being taken by Abstergo and after leaving the farm. The final confrontation would be on the lost continent