There is no real downside to having long arrows, as long as they are in tune.
Howard Hill said that any arrow length in front of the shelf was a waste. He had two reasons for saying that: he shot wood arrows with very heavy bows, and high spined wood arrows are more difficult to find in longer lengths, and he checked his draw length by drawing the arrow until he could feel the back of the broadhead touch his forefinger. His two reasons mostly don't apply anymore, although I’m sure there are those who shoot wood arrows and draw the bow exactly the way he did, or at least wish they could. The modern thinking is that your broadhead should stay at least an inch in front of your forefinger for safety reasons.
What is important is to have all your arrows the same length. For people who aim using the tip of the arrow, the reason is obvious. But even for instinctive shooters, I think the subconscious mind notices the arrow length, although there are probably those who will disagree with me.
My feeling is that no one should cut their arrows shorter than 29”, because I think they fly best at that length or longer, although I’m sure a lot of people will disagree with me on that too.