Imo Tobi should have been someone Naruto met before or had a bond with.
Reason.. When he's unmasked no one will care(Narutoverse.. not real life. Some will probably poop bricks when they see Tobi's face.)... much. Since it doesn't seem like no one's met him before, say if... Naruto breaks his mask.. You want some type of shock reaction... instead of, So that's the man behind the mask.
Like when Haku's mask broke.(But we wouldn't want Kishi to repeat the same scene.)
Tobi could be the Sage of 6 Paths himself... Naruto wouldn't care. Maybe the ones who've heard of him would.
Basically.. I want some type of emotion when Tobi is unmasked. By the way things are going.. It doesn't look like it will be any. Without that.. I don't care who Tobi is.
Kishi could proved me wrong...