Fair comment mate, I suppose it depends on your eye level too as to whether it affects your view. There is always the option of tinted Perspex too?
Tony.
Indeed - Us short a**es don't have to worry about such things.
I haven't got around to using the one in mine but
@Gail has her OEM mesh deflector installed permanently. It does take a bit of getting used to especially daytime as it slightly reduces your visibility. However, I expect that the mesh one aids wind flow by letting some wind through - the perpsex one I suspect causes eddies as all the air has to pass over, around it and through the cabin rather than some go through it. Don't know though if that actually causes air to flow over the top and reducing cabin wind further.
So, taking
@t-tony's idea further - a laminated perspex screen containing an LCD layer that you can dim (and colour code with your car). That would be