I saw some scans from the Hawkeye vs. Deadpool mini-series (Marvel: Constantly willing to flood the market with too much Deadpool stuff!), and it looks like the Black Cat is gonna be the big bad. So not only are other writers not ignoring what Dan Slott is doing with Felicia, they're picking up the ball and running with it.
Why do they always do that with the ideas I don't like?
I still can't say I understand it, but I had a possible explanation. Name the most prominent female villain in the Marvel Universe right now.
I'm serious, name 'em, because I sure don't know. I think a couple of Thanos' major lackeys were ladies, but I wouldn't say they're established enough yet. Medusa did the villain thing briefly early in her career, but she's mostly a hero (when her position as a monarch doesn't put her at odds with the FF or whoever). Emma Frost has been part of one X-team or the other for like 20 years now. Elektra's in a hero phase right now (as opposed to her "controlled by the Hand" phase).
I might expect Nebula to get a push after the Guardians of the Galaxy movie, but if it's happened, I haven't seen it (Note: It is entirely possible I missed it). There's Titania, but being She-Hulk's most consistent opponent isn't necessarily gonna put you on the A-list. The new Beetle hasn't really done anything yet. I'm not sure what the Enchantress is up to these days, Selene popped up in that X-Event Necrosha a while back, but I haven't heard anything recently about her, either. I'm not sure where the Red Skull's daughter is. Madame Masque is appearing in more books, between her involvement with Zemo in Avengers Undercover and her attempts on Kate Bishop's life in Hawkeye. Maybe it's her. Viper's the one who sent everybody after Wolverine, though, that might vault her into the lead. There is certainly someone blindingly obvious I'm forgetting, and I'm gonna kick myself when you mention her in the comments.
Point being, I wonder if Marvel is trying to get a high profile female villain, and they picked Felicia? She's been in a morally grey zone before, they sort of gave her a half-assed reason to turn evil, I guess. If she becomes Spider-Man's arch foe for a time, that would get her a relative level of notoriety.