G-S
Underfueling on the ramp - OK. Now unexpected long taxi out, you've burnt all your taxi and contingency fuel and you're not yet airborne - would you still be confident enough to overide the plan? Would the dispatcher's judgement be in any way coloured by the fact that his/her backside is not strapped to the aircraft?
You see it the decision to accept a runway/intersection is simply to
Issue a command to the aircraft over an interface.
So ATC are going to "command" a runway or intersection change - who vets the command to see if the aircraft is capable of executing a take-off from the new location? This isn't just an issue of comms, you're going to need and pay for at least one decision maker/checker somewhere in "the loop".
As for the medical emergency you say "Supervisor in flight control center is alerted, assesses situation and makes the call."
OK, but this supervisor will need flawless communications, a very good knowledge of the aircraft's route network, the aircraft's capabilities and limitations( in fact he/she might need an old fashioned type rating) and I'd suggest to avoid the odd unnecessary diversion the supervisor needs a feel for what is really going on in the cabin and the state of the patient, the sort of thing you only get from face to face communication with the cabin crew, and I don't mean a video link.... sound's like you still need a decision maker on board to me.
If you insist it can all be done remote by having "supervisor/s" on call how many do you intend having? (Don't tell me, one or two to save wages, "we don't over procure just in case" ).
How is such a supervisor going to cope when, say, three aircraft contact him, all at the same time, "asking" for decisions because their destination field is out in thunderstorms and their fuel is getting very close to the minimum need for a diversion - oh and they
all need the decision
right now, and BTW one has had a lightning strike and no, you can't put two of the aircraft on hold
to sort that problem out...........far fetched? Read recent threads.
How would a handful of supervisors perform if presented with a mass turnback from the Atlantic tracks, cf. 9/11
Given the state of "computing" (sorry for the old fashioned term but I briefly flirted with computing and programming before it was IT and well before I.M) as I see it for the forseeable future if you remove the decision maker from the aircraft then, each flight IMHO, will need a dedicated supervisor so you're not going to removing that many employees from the payroll any time soon, just moving their workplace, and in addition you will certainly need a 100% reliable data link - is there any such thing?
We all know we'll see unmanned freight ops of some sort probably in the next decade, IMHO you may see large passenger aircraft single pilot ops supported from "Mission Control" in the next 20-30 years, but commercial unpiloted, remotely commanded ops...not in my lifetime.....
As an aside:
no one will be running an APU on the stand 20 years from now.
I admire your optimism - I reckon large parts of the world (esp, parts of Asia and Africa) you'll still be running APUs of some sort in 2050.