Very soon you can turn off the app store on the device and still push apps. Right now we use district managed accounts for the iPads. This lets us control which apps go to which devices. At the end of the year 'refreshing' the iPads just takes a couple of keystrokes. Removing a manually added app is hands-on pain; removing 30k manually added apps is impossible. 30k is a very small, number when we first started we had students putting over 1000 apps on their devices in 4 months. Refreshing the iPads was a nightmare. It is not nice for little johnny to get ZombieSlayer5 with 'BOOM' headshot action.
I'm hoping these updates will allow me to simply start a task or two in Profile Manager that will wipe iPads and then install necessary apps. A lot of the advice I've gotten from our Apple reps is predicated on us having a lock-and-charge cart with a big USB hub; we don't. And I'd prefer NOT to plug in 330 iPads two-at-a-time with my MacBook Air. But I guess I'll find out this summer...
Also, does anyone know: if I go ahead and update our server to El Cap when it arrives, will I be able to push apps to iOS 8 devices? Ie., be able to disable the app store for everyone as soon as the server is updated? Or will we have to wait for all iPads to have iOS 9?