Company of Heroes already has a semi-dynamic LOS. Your troops won't fire at what they can't see. (Example: Hide behind the church, hide behind the hedge, hide behind the tall stone wall)
OSTHEER IS DONE WHEN IT'S DONE!
^^THIS^^ is what I'm kind of worried about. I don't like how, even if you can't shoot, you can still magically see through buildings and such. It provides a magic safety net in crowded areas. I hwant to see a cityfight that is real hell, because you can see a long way down the streets, but not around the corner.