Given that Adobe doesn't care about customer feedback and so there's no easy to find form for it, I'll enter it here.
Last year's (early this year?) changes to the reader UI are terrible. 99% of people just want to read a document, but every time you open it the full set of functions are listed, taking up screen real estate. Every single time, I have to go to read view, as it doesn't remember context from the last time I was in reader.
Then there's read view not showing the page numbers. I have to go to read view than go to view to add back pages.
Every time I open a new file, it asks if I want to check its security. I have to uncheck that for each document and there's no place in options to turn that off.
In a similar vein, every new document is "being prepared for" and then no explanation of why it's wasting my time with a pop-up that's counting pages. Prepared for what? Why isn't there an option to explain and turn off the preparation.
There's more, but the overall problem is that Adobe has decided to show off what it thinks are cool features rather than help people use the product as it is typically used.
If there's ever a freeware replacement I can find, I'll switch.