First of all, 902, you have a lot of nerve trying to keep this thread on topic.
It seems to have wandered a lot.
Second, you make some very good points but you miss one point: not all dispatchers/call takers/etc. are capable of making some of those decisions. Coupled with that is the fact that the available pool of potential employees doesn't seem to be getting any better.
Oh, I'm well aware. Today, some organizations offer their public safety telecommunicators $27,000/yr (happening down south of you) and wonder why they come in for two shifts and leave without notice. And, the need for an EMD of some sort is only a
framework to establish a least common denominator. There are talented people, and there are people who are simply inexperienced. There are also people who, for whatever reason, can follow the guide cards, but cannot think on their feet. This brings the talented ones down, and the others up. Same with whoever's working the shift in the street. There are times you feel like they have your back and times you want to bubblewrap yourself and hide (at least I did...). At least this creates some "no matter who's working" level of service.
The bigger problem is when there's an ambulance mishap (I don't call them "accidents"), a certain physician always seems to make the morning talk show circuit plugging his "solution" to wrangle EMS. Mind you, that physician has never been an EMT or paramedic, and, to my knowledge, he has never taken EVOC or CEVO, nor has he responded as a motor vehicle operator to an emergency incident (to my knowledge). Why is the EMS community open to being wrangled in such manner? Where are they in self-governance and factual research/statistical data to control their destiny in such matters? It's the tip of a much deeper iceberg, as the structure of some EMS organizations wouldn't be tolerated in other public services.
As a long-time paramedic from a third-service environment, and someone who's managed a countywide E9-1-1 system, I'm fairly passionate about this topic, as I am about bringing EMS to the point where other health care "professions" are in terms of determining their unique body of knowledge separate from all the other peripheral personnel, like doctors, RNs, and "others" who don't exclusively perform the EMS function. Some of my fellow white hats have likened this to "fighting the fire from the [dispatch switch-] board."
And there's LEO guide cards and fire guide cards now, too. Everyone knows the job better than the people who do it - and they'll tell you.
EMD has greater value when it advises, but not when it directs.