SharePoint 2016: The future is hybrid
The same fate appears to be in line for SharePoint 2016, expected in mid-2016. Although Microsoft has yet to release a beta version (one is expected by year end), the details it has released show that SharePoint 2016 is on the same path as Exchange 2016.
That path is a hybrid one, where the on-premises version is extended by cloud-only features, with the mix shifting from on-premises to cloud over time.
For starters, much like Exchange, the on-premises version of SharePoint has already been evolving in the cloud as part of Office 365 and as SharePoint Online. There are features in the cloud version of SharePoint that will not be brought to the on-premises version, such as Office Graph and Delve.
Some features of the on-premises version will take advantage of the cloud, in what Microsoft calls "cloud-accelerated experiences." That leads ultimately to hybrid configurations involving on-premises SharePoint and the cloud-based SharePoint Online, letting your users can take advantage of features that exist only in the cloud version while letting you still run most of SharePoint on your own servers.
Here are three examples of "cloud-accelerated experiences":
SharePoint deployments will no longer allow for a stand-alone deployment with SQL Express (even if you’re simply trying to set it up as a quick dev or test server). However, you can still install SharePoint 2016 on a single server with SQL Server installed.
Unlike Exchange, which has steadily reduced the number of server roles you can deploy from five roles in Exchange 2007 and 2010 to three roles in Exchange 2013 to two roles in Exchange 2016 (Mailbox and Edge Transport), SharePoint is going the other way: You can deploy a single server farm or a multiple-server farm where you choose the following roles:
In addition, there are changes in the authentication options, with Azure Active Directory trusted by default. But SharePoint 2016 will retain backward compatibility for previous authentication methods (Windows Claims, Forms-based, SML, and so forth). Microsoft is apparently moving away from Windows-based identities in favor of claims-based options.