Aaron Bertrand has written a nice blog post about tempdb improvements in SQL Server 2016. You can read more from http://blogs.sqlsentry.com/aaronbertrand/sql-server-2016-tempdb-fixes/.
The most important feature for me is ability to configure multiple files to tempdb during the installation. Currently, you need to do this manually and restart the server which will not be required with SQL Server 2016. In the configuration it also check the number of cores and provide the guide line as well.