ArmA 3 is really shaping up to be THE NEXT epic mil-sim but there is a lot of work to be done. The water looks great so far, but is missing several realistic parts that should not be difficult to implement and would improve the visual fidelity and realism of the game.
First off, let me start with a mental image. You are visiting relatives on the coast and there is a severe storm with strong gusts of wind and waves. If you were to look at the ocean, what would you see? Rolling water in multiple directions? Or would you see rolling water following the wind and tides? Next, would the waves be normal, or would you see white caps due to the strong gusting winds? What is missing from the water elements is reaction to the other elements. If you set the environment in a mission to a strong storm with strong gusts of wind and large waves, there should be white caps and waves rolling into shore and crashing against the rocks. Next, everyone talks about how bad the rain is at night and I agree. I must include though that when there is gusting wind, especially in a thunderstorm, we tend to see "sheets" of rain. Perhaps it could be coded in that during strong wind and rain, you could see periodic "sheets" of rain to add to the effect of the presence of wind. Like with the waves, the wind is not readily apparent. The wind should affect more of the environment other than the grass and trees. When you drive in a vehicle, you should see water droplets on the windscreen. When it is raining, the wipers should automatically turn on. The interior of the vehicle looks great. Enhance the realism a bit more with how the weather interacts with the vehicle. Does the vehicle rock due to strong gusts of wind? Does the rain striking the windscreen get heavier thus making it harder to see well at higher speeds? Does the rain show up in the beams of the head lights?
When it rains, does the ground get "wet and muddy"? Do puddles form that when you walk or run through, you hear a splash sound? Does running through wet terrain affect your speed? If you are inside a building with a metal roof, do you hear the characteristic plinking sound from the rain? How about when you are in a shingled building, does the sound differ?
The rain should be transparent and only become visible at night when you use lights. That way you would solve the issue of the rain blinding you at night. Realistically speaking, when you walk outside at night with no lights on and it is raining, does the rain blind you to the point of becoming lost? not likely.
When it is windy you should "hear" the wind blowing through the trees and when you are inside, you should hear it whistling by.
After it rains and the sun comes out, the terrain should dry back up over time too.
Lastly, the clouds are great with being volumetric but when it storms or is overcast, there tends to be a strange circular motion to the clouds and they no longer appear realistic.