If you want a flat state space, you could always just go back to B727-like controls but implement them electrically, such as in the back-up direct-law control to the B777 FCS. But no one would buy your airplane. They wouldn't just not buy it because it was old-fashioned. They wouldn't buy it because the generation of airplanes with digital control systems has by and large a statistically significantly better safety record than older generations, and most people who buy these airplanes think it has something to do with the digital control and flight management systems.
You most certainly have much more expertise in this field than me but you will have a hard time making me believe that no one would buy an A320 because it's T/L are fitted with motion feedback mechanisms...
I would even venture that regardless of the pontification about the HCI community and the supposed irrefutable quality of the AB FWB software I'm rather convinced that there are
common sense improvements that could be at least
considered to improve those systems which I still see as contributing factors to this tragic - and not unique - accident.