I'm sure they'll offer a free upgrade option, and that it'll run like Win 10 upgrades. One thing Microsoft did do well with Win 10 was they worked out a large majority of issues that come up with Windows upgrades. Back in the day, it was a joke to consider doing an in-place upgrade of XP to Vista, or Vista to 7. With 7 to 8.1 the upgrades started to get smoother, but the fact that your computer gets installed with a new OS (Windows 10 whatever latest version), and you keep almost all of your apps without needing to reinstall - that's pretty impressive.
I honestly hope that we get the option to have a more traditional start menu. Heck - give us more choices with how we decide to use the OS. Whether classic start menu, Win 10 style, Win 8 style, etc. Somebody prefers one more than the other. Why make us install a 3rd party app to do what could be done out of the box?
I actually miss the days of installing an OS, and staying on that OS for the next 5 years. No bi-annual OS upgrades to potentially break something. My 2 cents. I'd rather know that the current computer I have will be functioning as intended the entire time. Like I said, MS has done great work in improving the upgrade experience... but upgrading the OS to that capacity every 6 months seems a but much... why not every 18 months at least?