He's not too far behind the 4 spot, he'll probably pull ahead more over time. I think if YJ: Outsiders continues to do the character justice and Batman and the Outsiders does well we could see him shooting up fast.
I'm not wholly surprised John pulled ahead, but Vixen had a pretty big lead early on and up until this recent bump she was able to keep pace and maintain it.
Wallace has been the only real surprise for me so far. I feel bad for the little guy xD