For the engine part, forget about the Suburban and the Corvette. Too many variables. Let's use something simpler and easier to imagine.
Get a 5lbs plane with a .50 engine turning a 12x4 prop at 12500 RPM and a 10 lb with the same engine, prop and RPM. The power trasmited from the engine to the prop is the same in both cases, and so is the thrust. But which will accelerate faster?? The load on the engine is the same, but the results are very different.
Put that in a control surface. One that needs 30oz to be deflected will deflect with 30oz torque, but much slower than if you have a servo applying 60 oz on it. I guess this is obvious.

Now, about which surface needs more torque. We need to see which has the largest chord, area and deflection rate. Usually it's the rudder, but in some cases it can be the ailerons (see the 40% planes with 4 servos on the rudder but 6 on the ailerons). The rudder, when on KE flight, will require a lot of "holding torque", due to the high deflection coupled with a considerate speed to make the fuselage produce the desired lift. Why a plane, when slighty banked (i.e. 80 degrees) in KE flight can fly slower than at fully 90 degrees?? At 90 degrees the wing is not helping at all, so all the lift must be produced by the fuselage, induced by a large moment-arm created by the rudder. Decrease the lift needed, and you decrease the needed moment-arm. Less moment-arm, means less force on the rudder, which in turn means less deflection and less load on the servo.