Don't we already had an app store for servers called apt-get?
Isn't the distro maintainers the ones who define the release schedules? Doesn't Fedora or SuSE, for example, release the newest versions for Firefox, KDE to the latest on their current distro for example?
I think an Application Store for servers is something redundant, re-engineering the wheel.
But that's my 2¢.
EDIT: And I'm even talking about similar tools to tasksel.
I'd still prefer to use the ones built and maintained by the distro though.
I know, there are likely use-cases not addressed by these tools that others can fulfill, but Synaptic does work as Graphical apt/aptitude