Bisch: I agree that a well tuned arrow is more important than length and that length is always secondary to tuning.
However, the question asked for disadvantages of unnecessarily long arrow length. I acknowledged in my first post that a longer arrow is often used to get better tune, but suggested a shorter arrow of appropriate spine can also be well tuned to the bow. (Didn't suggest that he cut his existing arrows shorter.) Which route one takes is a personal preference. Wasn't trying to be argumentative or criticize the use of longer arrows, just listed some of the disadvantages/problems one faces when doing so.
A number of folks have also pointed out a couple of potential advantages of longer arrows -- extending the point on range and/or reducing the gap for those who use that method. For some, those features probably far outweigh the disadvantages I mentioned.
Rereading my second post, I see I must have been feeling particularly argumentative when I responded to your post, because I certainly could have phrased my response more respectfully. I apologize.