Game got too ambitious over its' development for the PS4/X1. Not the first time it's happened. Won't be the last. Ultimately, they couldn't leave the money on the table. With the patch, it'll be playable, which matters most.
The game also needed another 6 - 9 months in the oven in general. They'll iron a lot of bugs out over the course of the next few months, but this was never going to be a smooth launch, especially on last gen hardware.