I'm assuming they didn't want to reveal how he looked in the opening. I mean, really, I was shocked when they showed us Demise's design. I would never have expected them to show the final boss of the game in any form or fashion. But Ghirahim is clearly depicted in every way, so that's the reason I used the picture.
Well, I may be in a minority with this, but in my opinion it's no way as crystal-clear as some people think that the guy on the left is really Ghirahim.
Ears: As far as I can see, all similarity between him and Ghirahim are the pointy ears, which means nothing to me because even all Hylians have pointy ears.
Hair: We can't even see if that guy is bald or has hair (it's too blurry) and which style or colour it is, therefore no comparison can be made to Ghirahim. In case of doubt I'd rather vote against it because Ghirahim has quite long hair which should be visible in the silhouette but it's not.
Eyes: Ghirahim's eyes are quite big and horizontal and line up with his ears, while the guy in the intro seems to have crescent-like eyes which are almost vertical at the outer sides.
Mouth: Same here, the intro guy has a very large and bent mouth while Ghirahim's is rather small and horizontal too.
Clothing: Not much to say here, intro guy seems to wear a thick wrapped winter coat while Ghirahim usually has a lighter coat (not wrapped) or no clothing at all..
Sorry, I'm not convinced.
I know that speculation and spotting patterns is fun and we Zelda fans (including me) do it all the time but we shouldn't sell it as fact unless we're 100% sure.