Nah, that picture doesn't say much. It's still hard to tell. Given the viewpoint and the way game graphics bug out a little with overlap, it's all quite a stretch to make big statements about significance of his ears. Not to mention the figure in the intro who you think is Ghirahim doesn't have one round ear, he has one that looks a little smaller. You could be on to something, but I highly doubt it.
As for the Vaati idea, I really like that. It's uncanny how much Ghirahim looks like Vaati and from day 1 that's been my theory. After all Vaati does go after MC Zelda's light force, which sounds a lot like part of the story told in SS' intro. And ressurection by Ghirahim would help explain how he goes from dead in MC to sealed in the four sword in FS.