Peter in that situation, the aircraft flirts with the stall but the stall in an L18C cub is barely a stall, it's more of a light buffet with a bit of nose down which unstalls the aircraft very quickly - it's not a CofA aircraft any more, but it was and there are ones just the same that are so I see your point. 60-65kts in the bottom of the curve as opposed to the speed unstable section but it is an extremely draggy machine.
Nonetheless a change in power doesn't automatically cause the aircraft to pitch for the speed that it has been trimmed to, equally if I'm flying a little faster and trimmed for say 75kts (top cruise speed being about 85) and pull the power completely it accelerates fairly quickly and I think it's not wise to assume that you will automatically pitch for an airspeed if you're in trim and change power but it is a technique that does work very nicely for a hell of a lot of aircraft and is unquestionably the basis for understanding the couple between, pitch, power, trim and airspeed.