Some observations.
There is a fair bit of confusion regarding static stability (which is what most appear to be talking about). The usual pilot training concept of balls in tea cups doesn't help much, unless you "get" the idea of looking at the force required to hold the ball away from the bottom of the cup and the associated desire for the ball to go to the bottom if you let it go.
In essence the following pilot-view requirements exist (considering an essentially constant altitude scenario) -
(a) trim for speed .. ie set up the aircraft to fly hands off
(b) without retrimming, you MUST require a stick PULL force to fly SLOWER, with the force increasing as the speed decreases.
(c) without retrimming, you MUST require a stick PUSH force to fly FASTER, with the force increasing as the speed increases
For (b) and (c) the higher the stick force gradient, the more stable is the aircraft.
(d) there must be no reversal of the stick force gradient (which is where SAS becomes necessary to fool the pilot into thinking that the plane is stable. In its simplest form, SAS is a variable downspring providing a preload to the elevator circuit).
(e) if you release the stick force, the aircraft must return to a speed somewhere near the original trim speed.
(f) the design rules impose numerical boundaries for these requirements but the line pilot can presume that the certification process takes care of acceptability (ie "trust me, I'm from the government ..").
A statically unstable aircraft can be flown by hand if you know what the situation is and know what you are doing but it is difficult, demanding, tiring and unacceptable for certification. For most pilots, a statically unstable aircraft is an aircraft looking for a place to crash.
Dynamic stability looks at making sure that the short period oscillation characteristics are heavily damped and that the phugoid characteristics are benign.
A dynamically unstable aircraft is not amenable to hand flying by a human pilot.
As a general rule, moving the cg forward increases stability while moving aft decreases stability.
There are numerous reference books on the subject and numerous web references .. all containing lots of mind numbing mathematics .. but you can find out what static margin and a bunch of other buzz words mean.
Alternatively, download AC 25-7A from the FAA website and search for the buzzwords. The text describes what the flight test folk do to establish stability measures during the developmental and certification programs.
Now, if you have some gee-whizz computers between the pilot and the aeroplane, you can look at reducing the inherent stability ("relaxed" stability) by virtue of the fact that the computer can sample and react far faster than the pilot ..ie the computer can fly an aeroplane which is considerably less stable than would be flyable by the human pilot.
However ... if those computers go "tilt", the military fast jet pilot has a panic handle option to live to fight another day ..... the civil pilot just has an enormous increase in workload and probably not much of a chance of winning a medal.