If they actually do pull the trigger on a Peter/Lily romance, it will never work from a press standpoint.
As someone who's taken courses in "African Literature" and "Black Cinema" in college, I can see that some comic fans will reject the pairing as being "an attempt at being overly politically correct."
Meanwhile, there will be people who will complain to the press (assuming the media picks up on the story) that Lily is too lightskinned or that she is betraying her black heritage by dying and straightening her hair (Maya Angelou famously has decried black women who do not have some form of afro, or "natural style" as she calls it).
A Peter/Lily romance would not end well in the media. I know a lot of fans were critical of Howard Mackie portraying Randy Robertson as a "Rastafarian Yuppie," but that was probably a more positive portrayal of the modern African-American (succesful and upwardly mobile) than the ditzy, out of touch with her heritage Lily is.
There will be some complaints no doubt, but not enough to have any impact. I think it would be great to read about, if handled correctly, just because of the amount of tension it would bring between Peter/Lily/Harry. I'm all for Peter having a new girlfriend, so long as it doesn't become "permanent" and they don't do the whole sidekick/confidant thing they did with Mary Jane. But two to five years publication time with Peter in a relationship with Lily or Carlie or someone else would be cool.