Where exactly has it been said (other than people possibly over-reacting) that everything will be funneled through the Microsoft Store. As I understand it both the ARM/Pro versions of Win8 have the Desktop area, so anyone can use whichever regular non-metro browser they perfer to download and install whatever program they want from whichever download location they want to.
Why isn't there this same hysteria with Androids and the Android Marketplace/Google Play? Or iWhatevers and the Apple Store? I would say that Microsoft are giving you more choices than either of those platforms.
All METRO apps will have to go through the Microsoft store according to Microsoft. Desktop apps which may come from the app store in the future, can at least be installed outside of it for now. If you want o use Metro and use a Metro app, it has to come from Microsoft's store.
This is one of the reasons people Hate Apple BTW.
On Android you can at least sideload apps without going through the store. (Maybe there is a hacky way to do this on Win 8, I don't know yet)
But the big deal with this over the iPad/iPhone and Android is, those ecosystems started out with an app store from the get go whereas MS is slowly changing an age old independent platform OVER to their own total control. A lot of future apps may NOT be available on the desktop, but ONLY through the Metro app store and that'll suck for people that don;t want to have anything to do with it. MS is splitting the windows developer camp in two and putting that burdon on the users.
Forcing metro apps through the app store is a dodgy definition of an additional "choice". It's wrapped in a serious concern for the future of app distribution on windows. No serious app developer (i.e. Adobe) is going to give MS 30% of their cut! (Without raising their price by 30% anyway). You think photoshop is expensive now... wait till you have to buy it through the MS store in Windows 9!
The time to start fighting against that "hysterical" outcome is NOW, not after there is no longer any choice.