Highlights of Visual Studio 15 Preview 4
The biggest change is the installation experience which is designed to reduce the minimum footprint of visual studio down to less than 500 MB compared to 6 GB in previous versions.
This is done by allowing the developers to install just the features they need. There is also enhanced support for C++11 and C++14 features as well as preliminary support for certain some features expected to be in C++17. Most notably Variable Templates and constexpr.