LOL, Carr definitely has an NFL arm. You don’t have to have the strongest arm in the league, but you need a minimum level of strength to make certain throws. Teams can cheat coverages to take advantage of, say, a slower throw on a corner route. That condenses space in the rest of the field without a team being able to take advantage of the extra space the defense is opening up.
I think Haener can shave some time off his motion, and if he has the trigger speed that he is known for, that further closes the gap.
At the same time, I don’t think he can tremendously improve his speed when throwing on the run or off base.
He may be limited to playing in a WCO, but worse things can be said about a player.