i think the problem is more that the air being sucked into the airbox is warm, not that the box itself gets warm... it could be that the air picks up some heat while traveling through the ducts, but it wouldn't be much... it's all plastic, not a great heat conductor. you'd have to heat wrap the ducts more then the box itself in that case, i think their total area is actually larger then that of the box.
better solution would be to move the intakes so that they catch colder air, but then if you change the length of the ducts, you'll fook up the resonating frequency...
no easy fix here i'm afraid. Custom airbox, or just leave it be.
it really is not that bad. people complain, because that's what the forum is for. we come here and whine about little details that irk us, brainstorm ideas, share experiences. we do not sing praises to our bikes here. why? we know we have the best! most of us rode many bikes before, and could easily afford to change for a different one... there is simply nothing better out there