The new UI is not great but neither was the old one.
The devs put out a video to address the complaints https://youtu.be/ovMwwccxMLM?feature=shared
The updates to the game itself in terms of graphical fidelity, audio and the new map are incredible but that’s just been ignored by the majority of the horde who are tunnelling on “UI bad”
Same. I had to lower some settings to get the same performance as the old engine. I imagine there will be room for optimisation on the new map/engine