this is maybe a bit late into the discussion, but i recently blagged a senior Gollanz editor into vetting a query letter for me in return for a drink. [she speaks about that very subject at cons sometimes so i knew it was right from the horse's mouth.]
the result was 15 mins worth of 1-2-1, while she literally scribbled over my draft, which was far more than i expected, and boiled down to:
make it shorter
only mention the main character by name
make it shorter
use shorter sentences
don't bother saying how it ends
make it shorter
see the idea? if i seem to be overstating, i should also say in that my original draft the paras dealing with the plot, ie the section that was trying to sell the story rather than dear sir-ing or talking about me etc, was already only 120 words. her version came down to 80. and i thought i was concise!
at the end, as she got up to go, trailed by 2 of 'her' authors and a lucky [all right, talented] guy who'd just snagged john jarrold for agent, she was kind enough to say when its finished send it. im still wondering whether that was serious, tho even if it was i guess it'll languish in a slushpile for years. but it did at least suggest that i wasnt too far off with the bit she'd looked at.
so short sentences, and a couple of brief, incredibly concise paras, seem to be it, leaving all the rest to the synopsis at a couple pages? leaving no excuse for her to stop reading before the end? terry