If there's one thing I've heard writers complain about, it's synopses. They hate writing them. HATE it.
Me, I love 'em. In fact, right now, I'm fighting NOT to start writing one for my next book(s). I've got a notebook full of ideas and some characters chomping at the bit but first I've got the work-in-progress to complete.
And therein, I suspect, lies the difference between those who hate writing synopses and me. I write synopses to sell a book before the book's written. I'm not trying to summarize a completed novel.
But even so, I still don't get the fear. A synopsis doesn't determine if a book will sell. The finished book does. Most synopses just have to show you've got enough "plot stuff" for a book and that the resolution is sound.
Why do I love 'em so much? Because that's when I'm most "free" with the story. I can put in whatever the heck I want, and often do. I can use whatever language I want, and often do. In the synopsis for the w-i-p, for instance, I used "This Old Castle," referring to the TV show This Old House, to give my editor an idea of what the heroine does when she gets to the hero's castle. Sure, that's modern and the book's medieval, but it gives a quick and vivid idea about that part of the story.
I do edit my synopses, of course. It's amazing what can get cut -- descriptions, redundancies, less important plot points or characters. And they do.
That said, I think anything less than a five page synopsis for a book is just not fair. Might as well ask for bullet points if you want something that short.