Empty list under "My content types" looks a bit scary when you jut installed your first content type.
Some possible solutions:
Offer the user to install a few Most popular content types at once?
Show some message below indicating that there is lot more stuff to add?
Don't switch the default tab to "My content types" until you have more content types installed?
Show all content types under one tab and offer sorting options.
improved first-time user experience with the hub