Personally, I find your point about apm quite reassuring. Although I find that when you move out with your army and are about to engage them, its better to queue some units (2-3) at production facilities than to not build any at all, as at bronze to gold people forget to build more units in the heat of battle. I've had several games where our armies would just about neutralise each other, but then i would win 3 minutes later because I built units and the other guy forgot. But, I agree, when you're sitting in your base, queuing units is a bad idea.
I think you also forgot to mention that generally, you want all your unit production structures to be constantly producing units- any units at all, unless you make a conscious decision not to (cutting a cycle to save for an expansion, saving for a key upgrade, or of course if the building is adding on a techlab or something). If you can't constantly produce units out of all buildings and keep up supply, you probably have too many production buildings. In bronze to gold, you can generally win by just having more stuff, and what better way to have more stuff than to constantly produce units?