"This wasn't an easy decision, but based on the feedback we've received, and based on our own internal tests, we felt there are adjustments and improvements we can make, including improving the co-op experience across all game modes, weapon and gadget balancing, as well as menu and interface navigation," Ubisoft said.
"We're taking a little more time to make these changes, and we think it's the right call."
Meanwhile, the closed beta will still start on 24th September 2015 as planned. "The additional time will allow us to further test things like infrastructure and matchmaking," Ubisoft said. "That extra testing and added polish will make for a higher-quality experience at launch."
Here's some great footage of the game from this year's E3: