I hope this can be done. The no grass though scope thing is particularly troublesome in my view.

This problem isn't restricted to stormy weather. I attached screenshot arma.jg above which shows this occurring in relatively calm water.

I think this would be a nice touch.

Happens to me too.

I agree on the ambient sounds. Setting wind force and gusts to maximum and standing next to some tress should be quite loud, but I couldn't make out any wind sound. The rain is also rather quiet.

One other thing that I miss from Arma II is the sound of your equipment shuffling around when you move.

+1 for optional. I would like to turn off all HUD elements to maximise immersion.

I experienced this too. Screenshot attached.