It's a flat shot, but it probably looks a little flatter because he's so tall.I agree. Reese is an example of a catch and shoot guy, with an excellent stroke, for all the complaining about his flat arc last year. I think Oats will find ways to use him more...
At 6' 2" I had a rather flat shot but it's because my Jr. High gym had a very low roof. It's how I learned to shoot, but I adjusted a little into high school and college. A higher arc usually is a softer shot, but you can be deadly accurate with a flat shot.