I’ve had quite a few chicken coops and tractors over the last forty-five years. For coops, I strongly advise making it easy to get in and out of with cart or wheelbarrow loads of bedding (in) and manured bedding (out). So you want it on the ground with a wide doorway. Preferably with an airlock entry — one door, then enough room to close the first door, then a second door. This will minimize birds escaping while you go in and out.
You also want good headroom, for your sake. I have chickens in three different structures right now; two were here on the property when I bought the place, and one was given to me by a friend. The one my friend gave me is elevated, and really inconvenient for getting in and out of it; once I’m in, there’s not enough headroom for me to stand straight. The other two both have low ceilings and I have to be careful not to bump my head. I’m short at 5’3″; when someone taller visits, they have to duck down.
It would be really handy to be able to collect eggs and fill feeders and waterers without having to go into the pens, too. I don’t mind going in with my birds; even my roosters are pretty well-behaved. But it would speed daily chores up to be able to just go down the row taking care of things from outside the pens.
All of my current poultry housing has at least one wall that is mostly wire for good ventilation. In the deep south, you could have all four walls wire (small-mesh, to prevent predators from getting in, and heavy-gauge wire to keep predators from tearing holes in the wire), with maybe sliding doors to cover the sides most of your wind comes from in a bad storm.
If you plan to try to breed your own replacement birds, the ability to divide your coop into at least three breeding pens is useful, too. You don’t need to keep them separated all the time, just divide the birds into breeding flocks about four weeks before you intend to start collecting eggs for hatching. So the dividers could be wire panels that could be taken out most of the time.