[prescojan]

Usability significantly decreased - now you have to go into menus to do anything. Yes, the interface may look cleaner, but you are not supposed to admire playpen visuals, you are supposed to press those now hidden buttons first of all.

[wizzwizz4]

I think the discoverability has increased, though. There are multiple ways to "run" the code, all next to the "run" button (which will automatically change to "test" if you put tests in your code), and compilation options are next to that. Stuff like Clippy and Rustfmt is in the "tools" section.