I regularly rev my engine on the open road to 5k+ to remind my engine that it's a performance machine
I don't see how downshifting is any harder on the car than upshifting anyway, it's the same only in reverse, and in automatic transmissions, it automatically downshifts as you brake, so downshifting in a 5-6spd is essentially the same thing, as long as you don't rev down from a high RPM all the time, be sure to put most pressure on the brakes. I try to keep my downshifts at the 3k mark every time I down it....such as, at 40mph I can downshift to 3rd without a jolt and keeps it under a good RPM, 25mph to 2nd, and from there I drift to a stop using brakes only with the clutch in.
Assist the brakes by downshifting, not downshifting to assist the brakes. Brake pads are cheap, clutches aren't.