Well the main problem with mesh is that it seriously cuts down the light entering your eyes, it also means that most of the light enters from directly infront of your eyes in fairly parallel rays with big gaps that your brain will need to fill in for you. This may cause your eyes to fatigue quicker than without them.
Letting more light through will mean you will have more light for the rods and cones to deal with. Your brain is pretty good at filtering bits and filling in the gaps elsewhere so any additional light may help even if it is just vague shapes.
It could be worth investigating although the holes might cause the polycarbonate to be weak or may cause too much distortion to be useful. The alternative could be a way of putting the goggles together so there is more air flow, or perhaps even two layers, a warm inner layer close to your skin and a cold outer layer with an air gap, this may reduce the likelihood of condensation occurring.