Ubisoft is planning more Assassin’s Creed games as we already know and after Ezio and Altair’s stories have been wrapped up in Revelations Desmond gets to take centre stage.
According to Ubisoft Montreal’s Alex Amancio the next game in the Assassin’s Creed franchise, whether it be number 3 or another spin off will be the grand finale of the Desmond cycle.
Assassins Creed Revelations is the end of the Ezio cycle and
the Altair cycle, and it really sets up whats to come from the grand
finale of the Desmond cycle,
It has also been mentioned previously that a new character will be introduced for the 3rd main game in the franchise.