There are some topics with critisism of 2.7 update, but most of them are incomplete, some are just pointless ("oh, I didn't noticed modules can be moved!") so I decided to put my own point of view in one place here.
I am using wordpress on 4 of my web-projects. And I updated only 1 of them to 2.7. And I will not update other until it gets better. why?
1. Admin color theme is awful. It is not contrast at all.. Not everybody has such wonderfully tweaked monitors as your designers. And after spending like 6-7 hours near the display it is quite uncomfortable to spot the difference between white and "a-bit-darker than white". All that admin panels mess into something completely unreadable.
2. Narrow icons on "Html design mode" is a tragedy. Why someone made them different from the icons in normal mode???
3. flash upload ceased working in opera (latest). I have to use browser upload. And it is not convenient.
That was things I don't like the most.
I also hate that left navigation. Because all that pop-up menus suck. They are phony and stupid. I don't mind navigation to take more room, but I do mind to see all that.