Following Apple’s big, beautiful WWDC keynote (we’ll have more on that later). it appears that Apple has opened up the download page for iOS 10.3, which likely enables some of the new cloud-i-ness of iTunes.
From the download page:
Automatically download new music, app, and book purchases to all your devices. Or download only the stuff you want to just the devices you want.* It’s all part of iTunes 10.3.
It seems that some of the syncing between devices will be managed strictly through iTunes. I haven’t yet been able to download it (once I click the link it redirects me to the download of 10.2.2), but I’ll share more with you when I get my hands on it!