[This is part 3 of the Minecraft/Windows saga. Go back and read part 1. Or part 2.] So if all this Minecraft noise isn't about closed marketplaces, then maybe it's about changes to how desktop applications get installed/run on Windows 8. That must be it, right?
Windows 8 will run all your existing desktop applications from Windows 7. Windows 8 simply introduces new channels to advertise and obtain software for your PC. A common mistake is to confuse Windows 8 with Windows RT, a subset of Windows 8 tailored for devices (like how iOS is a subset of Mac OS).
Here's a chart showing app options available to users, starting with Windows 7. As you can see, Windows 8 didn't lose any features. To claim it's closed or more restrictive than Windows 7 is just completely bogus.
Rev 1: Changed marketplace accessibility row label, removing the 120 markets it's not clear if App Store reaches 120 markets. (Not likely.) Added the 120 number onto the value for Windows 8 in this row.