"Example: while doing a loop, you can stall while going straight up, upside down at the top, or when going straight down. The resultant (temporary) aircraft motion differs, but the principles are the same.

Do a loop while going straight-up, pull on the stick until the airplane is stalled, and stomp the rudder: you just entered a spin while going straight-up. Horizontal plane? Snap-roll. These resultant maneuvers are temporary, and given enough time, would end in a familiar stabilized spin."

That's a very good point. I was meaning to point out, from a straight and level perspective, that "the slip" is relatively stable while "the skid" is not (in high wing stable airplanes). Once again the example is the falling leaf maneuver.

"Never had it "pitch down" on me like you describe in any situation. Think about it, how would that be possible? "

I actually have no idea. I'd lightly slip all the time with 40 degree flaps because it was a very tight runway. The nose down would usually happen if I applied full rudder and held it. Assuming a CG at its forward limit and airspeed constant.