For winter I'd partially cover the openings so they aren't sitting in a cross draft at night since there is a large opening on each side.  I'd also probably make the floor solid and cover with bedding, maybe put down a piece of vinyl flooring, to make cleaning easier.   I personally don't like trying to get wire flooring clean.  I'd also put a lip across the front of the nest boxes to keep bedding inside.  You also might want to put down an apron around the coop to prevent critters/predators from digging under.