It was more likely the social media backlash. Gail Simone did a pretty good rundown on the variant cover process several weeks ago when Frank Cho split from doing variants on Greg Rucka's Wonder Woman. The majority of creators do have some input on the standard cover for their book, as it's a representation of their work.
Variants, however, are handled more by the art editor and variant artist only. This is because variants are done more as an incentive to retailers to increase orders rather than to act as a representation of the creative team's work. The only time there's an exception to this is for more A-list creators like Rucka, Johns, Bendis, Snyder, etc who might rock the boat if they have objections.
Cameron Stewart, Brenden Fletcher, and Babs Tarr are great creators but they ain't A-list.