I think the reason it doesn't heat up as much for me is that I don't do "long inhales" - I am a micro-doser. When I take a draw, it's hold the button, wait for the vibe, draw for a 5-count, release button, and keep drawing for another 5-count to catch any remnants. So only 5 seconds of actual fire-time. I can certainly see why a longer draw would make the long stem more comfortable.
I'm using dzoinp's mod, so the permanent dome screen ensures my load is away from the heater. This arrangement also puts the CU close to the "mouth-end" of the stem, but the vapor's cool so that doesn't bother me. I think the only reason I'd
need to use the long stem would be if I wanted to load a GIANT bowl.