Shopping for equipment is a particular rough spot, in my opinion. Because the actual stats only show up when you inspect, comparing items goes from clicking one then the other to clicking one, clicking inspect, clicking back, clicking the second item, and then clicking inspect on that. Regular items have their full description available without inspecting them, so I don't see why equipment stats should be different.
Requiring more button presses and giving less information seem to be at the heart of a lot of my issues with the new UI.
For the ship, having shortcuts at the entryway would really help - if you could select storage or sleep to instantly travel to the relevant rooms and open their menu, and had a "back to entryway" button you could use anywhere on board would streamline things a lot.
The save and load menu also threw me off - partly because of CoC2. I'm used to clicking the slot, then choosing whether to save or load, not the other way round. Because the file menu defaults to save unless you specifically choose load, I ended up overwriting a save I was trying to load (I know it asks to to confirm you'd like to overwrite, but years of being asked to confirm whenever loading or saving has made confirming basically happen on autopilot for me).
I don't expect we'll get the old UI back, but here's hoping the new UI is updated to be easier to use once the bug fixes start dying down.