The FAA doesn't even mandate dispatchers for EMS, (or any other Part 135 operation, for that matter) much less any certification or training standards. Only Part 121 requires dispatchers. The last Part 135 revision took several years, and involved a lot of wrangling. I was involved in the helicopter rewrite to some extent, and it was done by the big operators, with not a lot of EMS input or thought. I don't expect another major revision soon, and requiring dispatchers would be a very major change.