I'm sure, as much as it would immerse players in the battlefield, I say its really not needed to be quite honest. It is just a little bit too much for the players and some people might not have the hardware to run expensive shadows in big maps.
I understand that you want to add this in order to stress test however we are currently doing the stress test on the new box just to test the server resources, These weather mods are not more server intensive than client intensive. So a lot of clients will lag a lot for no good reason.