Thinking about it in context of the show, it seems like most of the characters have a latent ability. Rock has Gates, Naruto has Kyubi, Sasuke/Kakashi/Itachi have Sharingan, Hinata/Neji have Byaakugan, I suppose Sakura could have Inner Sakura to open (on technicality), Gaara has his incomplete but more powerful form... the people that don't have a second form will get a second special move, although I think that everyone with a second form also has a special related to that form as well. There's supposedly pros and cons with gate opening, like how Rock gradually loses life when he does it. If this is true with everyone, I'm stoked.