I've just realised how I filter constructive critique, so am making a note here in case it's useful or in case I forget.
People find it very hard to offer critique on something without colouring it with their own perspective: how THEY would have written the show, had it been theirs. This has the best of intentions, but is the hardest thing to see through.
So, most often you'll hear a comment like, "I felt that the main character needs a song at this moment" when actually, what they mean could be one of these:
1. The way you've chosen to use song in the show as a whole means that this moment stands out as an obvious song choice according to your own rules, that you have then for some reason chosen to ignore. That reason is not a clear dramatic choice, and is therefore distracting.
2. In most musicals, this moment would be a clear candidate for a song, so you might want to look at a) why that type of song-choice moment exists in so many musicals - which is about as close to a musical theatre writing rule as we will ever get - and b) why you have specifically chosen to break that 'rule' for storytelling purposes, and c) how successful that attempt has been in terms of what you want to communicate to the audience.
3. They just don't think there are enough songs in the show, and are suggesting a place where THEY would put one because they don't realise that they want to say, or that it's okay to say, "This musical feels a bit song-light".
... or they could mean that this is the character with whom they most closely identify, in which case you might have over-emphasised a non-essential character at this point in the show.
... or they could mean that this scene seems more important to them than you need it to be in the show, so they're missing a song in a big scene where, actually, there should just not be a scene at all.
... or they could just mean that if they were writing the show, they'd have made that choice of song-moment. Which is a pointless thing to tell another writer.
... and any number of other things they could have meant, all of which you as a writer must filter in order to find the comment that a) they really meant and b) is most useful to you.
After some kind of presentation of work to audience, I like to gather in as much written critique as possible from two kinds of people: those I trust creatively, and those I simply know.
After some time, I gather all those notes together and filter them. I keep most of the notes from the people I trust creatively, although I always re-word some of them to what they meant rather than what they said, as above.
I keep a pinch of the notes from people I know, because even if I don't trust their ability to give constructive critique, or their particular talents in the field of musical theatre, or their ability to speak to a writer as a writer rather than whatever their job may be, I do trust in their ability as a human being to relate to a story.
And then I go through them and try to join them up. If a lot of people made comments about one particular song, even if those comments vary greatly, I put those together in one place: something is clearly not working in that moment.
Once I have that re-filtered list, it generally contains two levels of notes: meta-notes on the major plotlines of the show or journeys of the characters, and mini-notes, on specific moments in the show like a song or a scene.
Then comes the key final step when figuring out what my rewrites will be:
I try to make all of those notes be true.
I don't try to discard them, or de-value them, or decide that they're not relevant because I don't agree. I try to make myself agree with them in some way. (I'm not manic about it. If I can't, I can't, but at least I try.)
When I do that, I think all I'm doing is over-riding my own sense of creative self-preservation. I think I'm trying to be as objective as I possibly can about this very subjective thing, because I have found it to be true that when you're writing, you cannot try to be you. Instead, you must try to just be, and only then can the 'you' part come out.
It's like breathing: it gets all weird if you start thinking about how it works.
Don't think, just breathe.
