Microsoft made a big announcement today regarding the direction of Mobile Application Management. They were conscious of the fact that users may not want to enrol their devices for Intune management in a BYO scenario and this prevented the use of MAM.
A new feature will be released as part of the November service update to Intune. We will now be able to apply MAM policies without the devices actually being enrolled in Intune. An Intune subscription is still required but the apps will be managed - not the device. As part of this month’s service update, Microsoft Word, Excel, PowerPoint, and OneDrive will support Intune MAM without enrollment. Support for Outlook is coming soon.
You can read the full announcement (which also discusses other new features) on the Microsoft Intune Team Blog