Springs can keep the stick centered to give a sense of center and force increasing with distance from center only. But Gs building with stick deflection load the seat of your pants proportionally so I wouldn't say that there is no feedback. There is just no feedback in the stick. I do not think that one couldn't learn to fly a system like that Many small airplanes with side sticks have very little actual feel or force feedback. They have tiny control surface widths and so little force. Full flying tails have virtually no feedback so people add servo tabs to them to give designer feedback. Anyway, my point is that you can fly sims, models, games with no force feedback. It can be learned. Pull back on the stick the Gs build up quickly. Pull back softly and the gs build slowly. One thing about digital controls is that you can put in reduced control volumes and limits that are triggered by G limits or speed limits. That isn't what I wanted to start with but it could be done. Accelerometers are fairly straight forward now. One could add modes to the system in phases. Mode switch between an established mode and a proposed or mode that is being tested until the debugging is done.