That's a very detailed review!
I'm a big AVR fan, but yeah... The current IDE is super buggy. In ancient history (AVR studio 4) it was way better!
Another weird thing with their AVR-ice hardware is that they sell a much cheaper version with no swd cable. However, when you add your own cable, you find out why it was so expensive... The cable header on the AVR-ice is soldered on upside down, and their weird cable assembly silently reverses it again to fix the bug! I really pulled my hair out over that one...
Now that it all works I very much enjoy using the attiny10. The assembly language is really nice. However I still code in a text editor to avoid the IDE...