As an ATC of 35 years experience (now retired), and having held a CPL with Multi Engine CIR for even longer, I would not even consider trying to "talk down" a "non pilot" in any aircraft I was not rated and current on. Even then I would be more comfortable with a suitably rated flight instructor doing the "talking down".
As I have not flown RPT Jet aircraft one of my first actions would be trying to get a suitably qualified pilot into the tower to try and talk the "non pilot" down. I suspect that is what the myth busters will be doing, getting another pilot to do the talking on an ATC frequency, not the ATC.
ATCs certainly do not have the knowledge or training to act as de-facto pilots anymore than pilots could act as ATCs.
I am aware that in the past there have been instances where suitably qualified (as pilots) ATCs have been instrumental in getting pilots out of trouble, but I am not aware of an ATC ever talking down anything larger than a light aircraft.
Now, if I was a passenger on the aircraft with a disabled crew................
