i was actually thinking the same thing... except instead of a clear 'bra'... i thought they can provide a glossy black applique that covers that sloped area.
the black would match the black trim on the a pillar and blend i think. clear would just look like an obvious cheap fix. you dont want it too thick cause it will look cheap... but maybe 1/4 millimeter thick would be enough to change the sound?
does anyone have a pic of the roof area exposed? imo, if the fix is a quarter size hole and expanding foam then that's ok. a quarter size hole is not going to effect structurial integrity. they plug it back up with a metal plug and epoxy anyways. the foam could add whatever is lost anyways from the hole.
i havent driven it in rain yet in s florida. next rain i'm gonna run out and drive the car
but i would see it needs to be addressed in future model years... i mean if it is that annoying, then its a car you cant recommend in states like... seattle washington. i mean the constant rain alone is depressing enough... the noice in the car will just drive them off the edge... literrally LOL.
but hope if it is a recognized issue they resolve it with current year.
the foam may be a solution for all model years.