You talk about Arnold's program and how its high rep - it is. I've read a few of his books (including his mammoth Encyclopedia of Bodybuilding). He definitely advocates a higher rep count, as he should - its bodybuilding. However, as you yourself pointed out, it includes the powerlifts. I actually am in full agreeance with you that for a beginner, a proper bodybuilding routine - one that also includes the big lifts - can see great results. That's how I started.
However, you talk about easy vs hard and all of that. Have you done a 20RM squat set? Its "light". Its "easy". That is, until you get past the 12th rep and your body is screaming at you...and you've still got 8 more to go.
The low rep sets are more intimidating, yes....but personally, give me a 1RM before a 5RM, and give me a 5RM before a 20RM, any day, in terms of how easy or stressful the set is.