"A pilot cannot possibly do such a thing with any precision with conventional flight controls flying manually"
I would disagree. (where can I find a smiley that shows how appalled I am at such a statement...)
In fact, it borders on a definition of a pilot!
If you can't do that then in my opinion you should not call yourself a pilot.
When we used to carry out stall check test flights, we were required to fly maintaining level flight while reducing speed at 1kt/second and check that the buzzer, stickshake and stick push all operated at the correct speeds and time intervals. These would not work if we didn't hold altitude.
john
"(c) low thrust = descent = reduced load factor"
Am I misunderstanding you, or are you saying that a descent means less than one g?!?