The no windows design issue could be solved with putting a screen in the back of each chair and giving choices of a small camera (front, back, top side, bottom side) for the view. I would love to be able to look out the front of the airline while it's flying.
It's emergency exits that are the biggest problem. Someone sitting in the middle of the aircraft could be a long distance from any emergency exit. Putting some in the floor wouldn't help if the landing gear is destroyed, and the plane is resting on the bottom of the fuselage. There's also a problem with excessive G forces in the seats furthest from the centerline of the aircraft that could make the ride uncomfortable. That's the main reason they're talking about this being a freighter, but even then it would be non-live freight. I don't think race horse owners would want their expensive horses subjected to excessive G forces away from the centerline.
American airlines had a camera in the front of their 707’s back in the late 60’s. Watching a landing was scary. The camera is fixed and what you saw was the runway jumping all around the screen as corrections were made during landing. I finally quit looking...just closed my eyes.