In trying to second guess you I note that the two "mistakes" I put in were women. I thought Maureen F. McHugh and Gwyneth Jones were more likely to help sell a collection than Lucius Shepard or Jeffrey Ford. (I've never even *heard* of Ford!)
But I am not going to assume there was definitely sexism involved. There could be many other reasons for chosing those names which might be perfectly innocent.
What gets me is it looks to me as though there was some effort made to solicit stories from women writers -- I mean, Maureen McHugh and Eileen Gunn are not (alas) hugely prolific, so I'm guessing they were asked for stories. But it's a bit pointless doing that if you're then going to slap a boy's own cover on the thing.
Huh, 4 for 5, my mistake being that I put in Lanagan instead of Nix. The lesson I take from this being that the choice of names is even more strongly oriented towards the US market than I'd thought - though this should've been obvious to me.
I think the logic was probably "put the biggest names on the cover". Whether or not the names chosen are indeed the biggest names, or whether it might have been better to sacrifice one or two of them to avoid leaving half the audience feeling shut out, I leave as an exercise for the reader.
Hah! Five for five! The best part is that, once I was done with my selections (which I made based on who I thought were the most recognizable names on the list), I looked them over and thought 'huh, no women.'
(By the way, Torque Control appears to be eating my comments. Any idea why?)
Nix is big over here, so far as I can tell. I know at least three people who are big fans of his, despite not being SF/Fantasy readers in general. By strange coincidence they're all women...
I've read one short story that appeared in (I think) F&SF, and I read Mister Monday and whatever the second one in that sequence is a couple of years ago. I wasn't blown away and have felt no need to pick up anything else by him. But the Sabriel/Lirael/Abhorsen trilogy is spoken well of by several people I know.
Page 1 of 7