Are you joking? That'll stir some serious backlash. It'd be logical from an in-universe perspective, but outing their most prominent female character would send the message that a female character can't be strong without also being gay.
I'll grant I'm generally pretty broad in my use of the word "fans", but in this case I specifically meant people who buy comics in specialty shops, not Gloria Steinem. (I only pick Ms. Steinem because she was a vocal critic of the 1970's mod era of the book; I don't actually have any reason to believe she'd have a problem with Wonder Woman being gay, particularly if she's aware of the character's genesis.)
The message isn't "A female character can't be strong without also being gay", the message is "There have been lesbian and bondage undercurrents to Wonder Woman's character for 70 years and it's time to acknowledge them overtly."
This isn't like Batman and Robin, either, where any homoerotic undertones can be dismissed as fans' (and critics') projections and not what the creators intended. William Moulton Marston clearly and unambiguously intended bondage/femdom/bisexual themes in Wonder Woman, from the very beginning; that's not up for debate (though I'm sure Fox News et al would happily pretend it was).
That said: you're not wrong; I can definitely see a hue and cry from people who aren't familiar with Wonder Woman's history (or are but argue that the past 65 years are more pertinent to who the character is than the Marston years) and who aren't anti-gay but nonetheless feel this is a betrayal of the character, or pandering, or a publicity stunt, or what-have-you.
And I'm certainly not saying that it ISN'T pandering or a publicity stunt. I'm just saying that, if it IS Wonder Woman, it's absolutely consistent with the character's history, the creator's intent, and it's about damn time.
And it might not be her, it might be somebody else. Like I said, I think Tim Drake would be a great call -- though they might not want to risk the "ick" factor of the inevitable "Robin is gay" -> "Batman is a pederast" false equivalency.
Then again, Tim's not currently Robin, so that would probably help with some of the inevitable confusion from the mainstream audience of people who know who Robin is but don't know the difference between Dick, Jason, Tim, and Damian.