Wouldn't Power Users be regular users of things like keyboard shortcuts, AutoHotKey scripts, etc...?
For example, 99% of my time is spent in seven or eight applications and use the Win-# key to jump between them. Win-1 is file explorer, Win-2 is web browser, Win-3 is email, etc...
For lesser used things I hit the Win key and start typing the name of the thing I want and then hit enter as soon as it's highlighted. The organization or size of the Start menu is not important.
The only feature I use that I would lose is small task bar icons, but that isn't exactly a showstopper for me.
If the list is what Windows' most loyal users are complaining about, Microsoft must be doing a good job. If anything, I think these changes will affect more casual users who spend a lot of time inside the start menu.