There is another big patch coming to Assassin’s Creed: Unity. With patch four it will, “patch will address issues with stability and performance as well as online matchmaking and connectivity (among other fixes and improvements).” It will be out on all platforms on December 15, 2014. Not sure how big the download will be but sure it will be a few GB’s. Think they will have the, now free, DLC called The Dead Kings soon after this. Do believe that DLC was part of the third patch which made for a big download. All they have to so is unlock it.
[Update] This patch as been delayed. Can read about it > here.
[Update 2] The patch was now out. It was out December 16.
GetBent57 