Yes, HSA was designed as a solution for these problems. It looks like a good solution, however as far as I know there is not any hardware platform implementing the HSA standards yet. Also Intel is unfortunately not part of the HSA Alliance.
Some HSA benchmarks from AnandTech: http://www.tomshardware.com/reviews/amd-a10-7800-kaveri-apu-...
Note: the tests seem to use OpenCL and while they mention, "Looking at the HSA-based results..." I find it strange they are comparing the numbers against an Intel Core i3.
It might be more interesting to compare OpenCL HSA vs OpenCL non-HSA.