Ubisoft has created an Assassin's Creed Unity live blog section that aims to inform fans of patch plans and provide a list of the most pressing issues that they are looking into for future patches.
We are currently working on our next update that will help address some of the specific issues some players are having, including:
  • Arno falling through the ground.
  • Game crashing when joining a co-op session.
  • Arno getting caught inside of hay carts.
  • Delay in reaching the main menu screen at game start.

In addition, we are already looking into many of the other issues you’ve told us about and we have more updates planned. This list doesn’t capture everything, but here are the most widely-reported problems we’ve heard about from you:
  • Frame rate issues.
  • Graphical and collision issues.
  • Matchmaking co-op issues.
  • Helix Credits issues.

While the launch has been nothing short of a disaster for many, it's nice to see that Ubisoft is going to (hopefully) keep on top of these issues with the game.