The gap between Masters and US Open is always long, with The Players providing a nice stopover along the way, but seems especially distant this year given the compression of the rest of the schedule thereafter - 3 majors and the Bridgestone in the space of 7 weeks, then the Olympics, then the playoffs, then the Ryder Cup. I am not sure the solution, but wonder if the PGA might be able to move to early May in Olympic years, maybe at one of those slightly more southern courses that can get so steamy when they play there in August - Southern Hills, Valhalla, Atlanta AC, and Kiawah all spring to mind among recent venues that might be more amenable to an early date, though it would probably mean the death of the New Orleans event.
And now I see they will be at Quail Hollow next year, although in the typical August window. It could have been perfect to make it there in May 2016.