Microsoft has a lot of innovation that they announced this week. For developers, the most important is the SharePoint Framework. This framework is an evolution of SharePoint to enhance the extensibility and customization of SharePoint sites and applications.
Over the years, extending sharepoint has taken many different approaches. What is unique this time around, is that SharePoint customizations can be accomplished using the web/mobile-based tools that are used throughout the software development industry. It is no longer necessary to study and large object model. It is no longer necessary to install a large, complicated dev/test environment. It is no longer necessary to use .Net-based languages. It is truly a game changer.
The official blog post about the framework is at https://blogs.office.com/2016/05/04/the-sharepoint-framework-an-open-and-connected-platform/. This includes a video that covers the framework at a high level. This a must-see video for all developers, both long-time SharePoint devs as well as those new to SharePoint.
There are a couple of areas that I think are important:
Groups: The Office 365 Groups experience is permeating throughout the entire service: OneDrive, Sites, Email. Your users will be in Groups, so it makes sense to put your business logic/data/services in Groups as well. Leveraging the Office Graph to publish data into Groups will be well received by your user community.
Continuous Innovation: The Office 365 service is continually improving. And Microsoft has announced that parts of this innovation will be coming on-premise thru Feature Packs. It is crucial that you development process can support this more-rapid pace of development
I'll be writing more on these topics in the future. So I encourage you to review the information released today to get a start on the Future of SharePoint.