Sioux City DC-10
Rat5 - I concur that there will be events such as the DC-10 that managed to "land" at Sioux City in 1989 after a center engine rotor burst took out all hydraulics to the tail surfaces. Al Haynes and the rest of the crew on that one managed to get it to the runway using just thrust control of the two remaining wing mounted engines. In order for that to be successful you need to have an airplane that exhibits a fair degree of inherent speed stability such that engine pitching moment can be balanced by pitching moment due to changes in speed. I think that today's configurations that have been optimized for performance with much less inherent stability would present a significantly greater challenge to the likes of Capt. Haynes or any control system designed for this purpose. The bottom line is that if you don't have control inputs that can independently control thrust and pitching moment there is no control system magic that will be able to bring you home.
In the Sioux City event, I believe Al and his crew found that they had to fly rather fast to be able to maintain pitch trim. I also recall that they were only able to turn in one direction so had to be creative with their line-up. That event is a huge tribute to how quickly and effectively pilots who understand the physics of their airplanes can innovate on the fly and make do with a very crippled bird. It is unfortunate that the DC-10 ended up cart-wheeling on the runway, but it was amazing that about half of those on board survived.
To design a control system that would be able to do much good in such a situation it would need to either have extensive information as to what surfaces and controls were still available and what had been lost or the control algorithm would have to be adaptive such that it could quickly learn what works and what does not.