Agreed, not sure where the idea comes from that Microsoft is going to limit software to only stuff from the app store, that is something much more likely to happen from a company like Apple. Microsoft is founded on the idea of running on lots of different hardware and running applications from lots of different authors. I would say there is less than a 0.001% chance that Windows 10 will ever be locked down to App Store software only.
If the OP has concerns about running a corporate controlled OS however, I would recommend a dual-boot between Linux & Windows, not Windows & Windows.
I have seen talk of a new cut down version of Win 10, that is I think available now, that does just this. I can't remember the specific name, but there were several different sources.