Ventilation is a good point. It gets pretty cold here in the winter. I think it should last the summer though. Maybe we can buy one of those dog kennels and put the coop inside? Kind of like this:
This could work (I've seen a number of people do something similar on here), but since snow load is a concern, I'd almost consider going with a carport rather than a dog kennel. You'll need to fence it of course but it gives you the basic structure with a solid roof.
As far as the actual coop you currently have, main thing other than overall space is the lack of ventilation. Obvious places to try and add some - on the wall facing into the mini run and in the triangle just under the roof. If you do have a solidly roofed run that this whole thing sits inside, then ventilation becomes a lot easier as the roof will protect vents from weather without needing to add additional covers or buffers over everything.