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Well, Microsoft does the very same, with their security updates.
aptitude checks available packages in a central repository, checks which need to be installed on the system, downloads and installs them. you can see the list of installed packages, when you run aptitude.
windowsupdate checks available patches in a central repository, checks which need to be installed on the system, download and installs them. you can see the list of installed patches in control panel / something.
if you are running a stable version of debian, you only receive security updates.
the only difference is that debian is your vendor for your os, office applications, games, browsers, sound editors, movie players, etc - almost all of the software installed. ms is your vendor for only a part of the software installed.
with a bit of abstraction, you can see, that ms is already using a package-manager + central repository to distribute a part of their software.
Seems like a dead point, since:
1. This is a beta product
2. The guy is working on an software update program.
So... If it is a HUGE issue for you, don't use the product yet, and wait... Or, if you can work with the current limits, enjoy your self.
it is not a HUGE issue for me, as i do not use the product and probably never will. i was just presenting my point of view - that i consider his solution worse than what we have now.