I'll add yet another message to the chain. The new UI is awful. I have a workstation/"creative" laptop with a CoPilot button on the keyboard. It was a genuinely useful feature that I used a fair bit. Now, the responses feel more generic and less useful, the new UI looks childish and unprofessional, and the CoPilot button doesn't even work properly anymore. Pressing the button brings up CoPilot, but pressing it a second time doesn't close it like it did before. Much more impractical, time consuming, and overall "clunkier" feeling.
Overall, I'm extremely unimpressed. I'll hope it either gets reverted or we at least get a way to bring back the look and functionality of the old UI.
On behalf of the community, we're disappointed. We expected better.