In an utter and absolute twist, Nico Muhly waxes rhapsodic about a totally sci-fi notion:

Oftentimes, I wish I had somebody who would just rush into my studio and say, here’s the deal with this piece: this part is awesome, and these two bars have to go. Or “those two bars are irrelevant.” I’ve written at length about this problem before; in the other Arts, both applied and otherwise, there are outside forces to temper the artist. Visual artists are restricted by the size of their canvas or the space their art will inhabit. Writers have editors! Can you imagine, composers, if you had an editor? 

And what I love is the way he defines an editor in the very next line…

Somebody you love & hate & trust & mistrust who has access to your music at any juncture?

…which sounds rather Jekyll-and-Hyde-ish, doesn’t it? Almost like some other version of yourself that you swoon and transform into: “Huh, what? Where am I? What is this? Who wrote this? I… wait… my god, this is crap!” Some other version of yourself with one difference, one impossible advantage: fresh eyes.