Pinehurst #2 in USGA, US Open 18 hole Stroke Play configuration will be released in about 2 months.
Later in the year Bandon Dunes will be added as a par 3, 18 hole stroke play course.
Apparently, Pebble Beach, scheduled for addition in 2019 has been moved forward and may be added as a full 18 hole stroke play course after Bandon Dunes.
It takes WGT about 6 months of work from start to finish to add an 18 hole course. So 2 new 18 hole courses per year seems to be the limit.
In 2015 we will get the US Open course Chambers Bay.
We already have the 2016 US Open course - Oakmont.
In 2017 we will get the US Open course Erin Hills.
In 2018 we will get the US Open course Shinnecock Hills.