The auto turret rotation speed was never slowed in the last patch, in fact, we increased the rotation speed when locked onto a target.

This my testing on a vanilla server:

https://files.facepunch.com/Alistair/February/10/2k59bw383n4/TSNkSOiADl.mp4

https://files.facepunch.com/Alistair/February/10/8921IU270Fc/lAO6cse7XU.mp4

I further tested with a variety of weapons, ammo, attachments and server performance and could not reproduce the results as in the video posted.