I love it and I think you did a wonderful job! Oklahoma has the the downside of very hot summers and winter cold that blasts directly from the arctic! Given that, I would get some sheet styrofoam or other insulating material for the inside under the tin roof. Lots of open area is good, and it is more like that is your run than your coop at present. Are you planning on more area for run? You can always wrap tarp on the sides for a winter windbreak, if you dont mind the extra work putting it up. I would add some on the upper half of the south, east and west facing sides for extra shade during the day... Especially if you arent home to see if they are doing okay in summer.
My girls like having an outside roost to hang out on, so I would keep that one outside, but move it to the center. A predator can get them through the chicken wire, so want some distance there.
I agree that I would enclose the area above the nest box for a nighttime roost, leaving lots of vent area, and I would add a hinged door and a sloped floor for easy clean out. i would put one roost in the center running the long way over the nest box.
Really, a very nice home!