I sort of agree however Allen's first couple years he had a solid number of great long passes. In my opinion his long range throws are off due to a combination of overthinking or overpowering the ball combined with a lack of catches when he does make a pinpoint throw.
Essentially, Allen might overthrow or underthrow a deep route, the next time he tries he'll adjust accordingly. On try 3, let's say, he throws a perfect arc to his receiver who proceeds to drop it. (Diggs, Davis, Hollins, the list is rather long) With the drop Allen feels the need to even further adjust to make the catch even easier and thus falls back into over/under throwing the receiver and the cycle continues.