All that said, a few suggestions:
Fill in the Version field in the app manifest. It will make it easier to distinguish which version we are using, expecially for people who use XapHandler or another app that shows the version number.
Sorting by app title is good, but for an app like this I'm usually less concerned by "How much space is this using" and more by "What is using all my space" so maybe have the option to sort instead by Install size, Data size, or Total (combined) size? That would be fantastic.
Great job already, though. I especially like the background loading; it really reduces the annoyance of the wait time.