But that is the answer. A package manager. Simplified installation for users, keeps things secure (as long as vendors push updates to the repos) and probably makes Microsoft some cash from selling stuff.
But it's certainly not a new idea.
I don't know where to look between the logo, tiles, sidebar filters, sign-up button, big text "tabs", forced uppercase, forced lowercase and that mysterious white pane at the bottom.
It all sort of makes sense and doesn't at the same time. It's a really hard one to explain. I think a first step you need to look at the typography. It's all over the place. If that's a Windows style convention, there's no saving the human race.
It's also not that useful to just have a massive tile-spread of things at the topmost levels. Keep editorial and design control over the first "Find apps" screen. Also make sure you're not suggesting things that people already have on those screens.
And why are there things without icons?
While the current version (1.5) is .NET/WPF based, we've switched to full C++/Webkit for v2. Results are impressive: launch <2s even on the crappiest PC we could find, <40Mb of memory footprint... and, best of all, the UI is just "fast and fluid"(tm).
[1]http://static.allmyapps.com/images/uploads/allmyapps_v2.jpg