SharePoint 2013 is not just a collection of lists and libraries anymore. It is a big product with lots of built-in out of the box services. We as SharePoint developers used to build a lot on the top of SharePoint, but with rapidly growing product functionality, there is less need for developing custom code. In fact there is more need for consultants that they know SharePoint out of the box services and features and they also know how to configure and use them. The new generation of SharePoint architects, have deep understanding of built-in services and their limits so that they can decide whether to develop custom code or just enable a built-in Service. This approach makes SharePoint development quick and dramatically reduces the cost of maintenance and support.
Developing software solutions that work across several devices and platforms is becoming increasingly important. With that in mind, Visual Studio 2015 attempts to streamline sharing code across platforms in a number of ways. This video provides an overview Visual Studio 2015's new shared project type and how you can use it to share code across platforms. The video also briefly covers portable code libraries (PCLs) and shares best practices for choosing a code sharing strategy.
To find out more information about cross device development with Visual Studio, check out this whitepaper on building mobile apps with Microsoft tools and resources, leveraging the Azure platform.