Alright, there's Reshiram with Fire/Dragon, Zekrom with Electric/Dragon, and Kyurem with Ice/Dragon. I don't see why Game Freak would suddenly abandon Kyurem's Dragon typing for these formes.Personally, I'm leaning towards Ice/Fire and Ice/Electric, if it's that important to you. Please tell me how this justifies something completely unheard of over type combinations that already exist.
Maybe next Gen (a bit too early but) they can do something like what they did to Rotom, and just do another type change. And just stick to the Ice/Dragon Kyurem already has regardless of it's looks and it's movepool.