I was sure it would be a she when i logged to the PBE and there were no soundfiles.
Vel'Koz as a female just works, for me - there really isn't anything gendered in the animations, and we hadn't had a female monster champion since Anivia. I've been calling it Viki. All it would take to get it to be female is just changing the pronouns in the lore and maybe tweak the voice acting pitch a bit. What do you say, riot? Is Vel'Koz the female monster champ we deserve?