I like John Hurt personally. Big fan. But I think I would've been positively blown away had it been Paul McGann that turned around to face them at the end. I don't believe the 8th Doctor was featured in the episode with Clara encountering the incarnations, so wouldn't it have been awesome for the reveal to be HIM? Or maybe Eccleston pre-Rose?
Another thing that confused me....Clara seems to just take it in stride that there have been multiple versions of the Doctor. Doesn't even faze her. The Doctor must've told her about regenerations and stuff off-screen, unless she knows it intrinsically as a result of Journey to the Center of the TARDIS.