TET, your point regarding Nr is certainly valid for horrid low inertia rotors like the R22 and R44 - I would want as much Nr as possible in one of those - read the R22 accident report from the latest UK AAIB, it makes for sobering reading about low inertia heads and how quickly low Nr can turn into NO Nr!
Ref torque though, as you slow the rotor down the torque goes up so your max Tq will be as you try to accelerate the low Nr back up to normal setting.
In the high TR pitch scenario we are talking about, you can use lower Nr to help manoeuvre and get a rate of descent - then, once you are near the ground at low speed (with a higher power demand) you can wind on the throttle a bit to help directional control.
Nigel, what TC can supply is a top-drawer simulator where such things can be practised over and over again.