Keep in mind that the Lowe's coop is for in the city where yards are small and an emphasis is on how nice things look. That little coop could be made for far less than $530 if it wasn't trimmed out to look so "cute". It's definitely something most neighbors would find to be charming.
I think it is adorable and as I have silkies, people expect "cute". Some modifications I would do would be extending the run. I won't be building this one but it has figured into the plans I am drawing up for the new coops. We want them all to match. I ultimately plan on building 5 and maybe up to 7. Adding wheels and moving them about to keep clean grass under them. I also want the top of the run to flip back for access to my birds and the roof will have a sliding track instead of a small door for access.
As others have noted, it doesn't have nearly enough ventilation. And the other thing I always think about when I look at a coop design is how easy (or hard) it would be to clean. Unless the back side of this coop opens up completely so you can easily rake out the bedding, etc., I don't think this design works in that department, either. But, those are two issues you could fix by modifying the design.
The other thing I think is good to have are roof overhangs.