Of the many, many flaws in your argument that FTD's should be able to immediately gain licensure to practice in the US, one is humorously obvious: How many FTD's are willing to come to this country and agree to work in the underserved areas you are using to justify the concept of immediate licensure in the first place?
Somebody Google Helena, Arkansas and see if you would like to live there for 5 years.
Or Guin, Alabama
Or Echo, Minnesota
Or the Southside of Inner city Chicago for that matter. Although the requirement by many states for FTD's to receive a DDS prior to licensure can be onerous, there are reasons for it. As an educator and clinician, I have seen the dental work of my immigrant patients, which was done by some overseas dentists. I am not generalizing to ALL FTD's, here, but much of it would be considered malpractice in this country. Which means big lawsuits. The state dental boards are not willing to take the risk that a given FTD happened to go to a 'good' foreign dental school as opposed to a bad one. There is no way to know. This is the primary reason most states require some level of education to be achieved in the US.
That said, good luck to you all. My wife is an FTD and has done quite well. Her DDS program was somewhat repetitive, but believe it or not she learned some important things during the program. She will soon have the required credentials to practice in any state in the country.