Like the idea of batch uninstall. Would be helpful after trying many apps.
Now if the Store could have a section for "permanently uninstalled". Right now My Apps is mixed between apps I actually use, and those that doesn't meet my expectation. It should be a useful data for developers too, data about if their application is tested by user and then removed.
Most of the functions can be thrown into the appearing App Bar together with Uninstall (invisible when checkboxes are not shown).
Hide Sidebar button is redundant because we have the Back button.
Select button is also redundant.
Not sure the difference between Group and Create Group.
Tools have to be in app bar, or better yet, in the Settings as this is part of the OS after all.
may be a third swipe[ to left] brings Customisation
Windows Phone has a gesture to bring out checkboxes, like in Phone, Mail and Messaging apps. Basically touch the left edge of the screen and the checkboxes will appear.