The Unnamed Brood was one of the characters in the crossover that were being used as antagonists in the storyline, and so depicting her as threat on the cover was perfectly legitimate.
Considering the Brood alien spent most of the time hanging around with Humbug that issue (I said I didn't buy it, not that I didn't read it) I think it would have been just as effective from the 'danger' perspective to have the characters on the cover being menaced by any of the other alien species present. You also could have avoided the entire 'La Blue Girl' connotations. Heck, Brood aliens have a scary face, couldn't they have worked that in somehow instead?
Again, you may disagree with that, but aim your critique at what's actually there rather than what you've chosen to read into it.
But wait...
The emphasis on the attractiveness and vulnerablity of the heroines was just one more layer to the emotional hook the cover was going for.
...That's what I was critiquing. I took the step from 'attractive and vulnerable' to 'sex and (the suggestion of) violence,' or, in short, 'sexualized violence.' I don't see it as much of a stretch. It is the tactic I disagree with. It does look a lot like a hentai cover, and I find it hard to believe that was unintentional, both hentai covers and that superhero cover were drawing on the same imagery and influences. I don't think you can judge the cover in isolation, you have to accept the baggage that goes along with it.
I am critical of the fact that the girls were dressed so provocatively. I am critical of the fact they chose to use the girls and didn't add Shang-Chi (Since I guess it would be gay or something to have a male manacled hero being slobbered on and threatened with tentacles?). I am critical that they chose to use the Brood even though they were likely aware of the connotations (though I am willing to give some leeway with this one). I am critical of the fact the girls all look completely helpless. I am critical of the whitewashed Misty. It combines to be a cover I am highly critical of for a number of reasons.
Oh, and for the record, they did make it out ok. Except for their book getting cancelled, of course. Shame about that one.
I know, I started picking the book up again with issue #14.