While I do have a gut feeling that Black Widow was fast-tracked over another Capcom character (be it Gill or anyone else) to address the lack of female fighters in Year 1, I don't think it's because of a lack of DLC females on Capcom's end. If anything, I feel like it's due to Black Widow possibly being the farthest along of the Season 2 characters, so Capcom fast-tracked her completion so she could be ready for Season 1. This would also line up with getting Laura Bailey, who was likely too busy with Uncharted: Lost Legacy to record for Chun-Li for the base roster, to come in for Black Widow. Laura's really the only option for Black Widow, outside of an unknown, seeing as Natasha's EMH voice actress (Vanessa Marshall) is already voicing Gamora.