Arm strength isn't really based on how far a QB can float a bomb. It is how much zip they can throw the intermediate routes such as the out route and the post. Those throws need to get there on a rope. Kordell Stewart threw a 70 yard bomb to beat Michigan in college. In the NFL he couldn't throw the intermediate routes.
Arm strength is but one weakness of Moore's. If that were his only weakness he would probably be alright in the NFL, but it is not. He is short. He also has slow feet. And to be picky he is left handed. Being left handed isn't a weakness, but it does require changes to the blocking schemes.