Originally Posted by dattier
Only because the character is a prepubescent boy; transposing itself is no big deal, just as operatic parts written for castrati are now performed by intact adult men, often exactly one octave lower with no transposition needed.
So many of Peter's songs are ensemble pieces, they'd end up transposing the whole show and having to rethink the ranges for every character in it. Again, not impossible -- but it would have a profound impact on how the show sounds.
I'm not saying it should be one or the other; it will be interesting either way, and for a variety of reasons.