Game engines are designed to be scalable for a range of hardware. Compared to the ps4, TW3 performs better on an i3/750ti combo @ 1080p with console equivalent settings. It's a gpu-intensive game, and the 750ti is essentially a little weaker than the ps4's gpu. You don't need to be a developer to understand this either.
The bigger issue here, however, is that the game now performs worse than it did with the previous patch. There is no justification for that.
The improved draw distance probably happened on PC, but the visual settings remain the same on consoles.
Oh please, "soo" big. That's your argument? The game streams most of its assets within a fixed radius, so the size of the world isn't an issue here. There are several other games that use Umbra 3/Speedtree, and they run fine.
Even Ubisoft managed to improve AC: Unity's performance with a patch on both the PS4 and Xbox One. There's no excuse for doing the opposite.