I love the idea of the different Focus modes. Hopefully they have some good profiles out-of-the-box. I imagine without a good set of profiles, most people will never end up touching it. Hopefully shortcuts can interact with the current focus mode.
The Safari changes are quite aggressive. I'll have to try it before judging it. I don't really use the tab bar that much. I tend to find tab expose works better for me. If that still works, this change will make little difference for me. The tab groups seems neat. I know that is a thing people are always asking for.
What is interesting is the contrast it has Firefox changes announced recently. Those changes got a lot of flack on HN for decreasing the vertical space available for the webpage. These Safari changes go in the opposite direction. The color changing feature further indications that the focus is on the webpage and not the browser.
Overall, I predict this version of Safari will be pretty unpopular on Hacker News.