Not in the survey but.... KF2 needs more female characters.
I'm usually against the idea of adding diversity for the sake of it. It doesn't feel sincere and more like a way to fill up a quota, as if to say "look how progressive we are ! We just added the character you wanted, happy now?"
It also doesn't help that Killing Floor does very little with its characters... As in they barely interact with each other the way Left 4 Dead does for example. And obviously, they all play the same. And since it's an FPS game, well...You can't even see their cool outfits anyway.
BUT. It is true that three female characters, including one which is behind a paywall, is depressingly low. Considering how many people wanted to see Ash Harding back, it's fairly baffling they didn't bring it back... and instead opted for Mrs Foster, which is arguably just a redo of the Fostinator himself. Maybe the original voice actress wasn't available? It's a shame anyway, plus considering she's actually military, it would have made more sense for her to be a mercenary than Rae the data analyst or Ana the punk who loves pipebombs.
I personally would have loved a move similar to the addition of Classic Briar and Masterson... How could would that have been if they brought back the Trader from KF1 with new lines? Of course, it would be non-canon, just like Classic Briar/Masterson surely are, but it would have been a great gift to the OG players nonetheless.
Finally however, I believe Tripwire said (and I'll be cautious saying so this time considering I was approximating last time I said something similar) that the DLC characters didn't sell as much as they hopped for. And considering they hired actors of quite the caliber (Claudia Lee Black and Gary Busey), that's fairly disappointing indeed. Making new characters costs money ! It's not just making a new model and coming up with a backstory : you actually have to hire a voice actor and this can be (justifyingly) expensive. Something they probably aren't willing to do so late within Killing Floor 2's lifespan.
And again, considering there's very little incentive to choose any character over another, except for personal preference, I can understand both Tripwire having different priorities...and gamers being happy with what they have. No offense to Gary Busey nor Tripwire, but I'm personally not willing to pay 10 bucks for a character that won't change how I play the game...No matter how fun and well-voiced he is.