About Dragon/Fire typings, I think I know why they are almost absent, so I'll write down my explanation. Only European dragons breathe fire. Myths about Mexican, African and Asian dragons usually don't suggest them breathing fire. Also, European dragons not only breathe fire, they also fly with the huge wings such a dragon has. Which means a Pokémon designed after an European dragon will usually carry the Dragon/Flying type, unless they decide to give it Dragon/Fire with Levitate. And other dragons don't breathe fire in the myths they are based upon. The closest thing to a classical fire-breathing dragon in Pokémon is Salamence as it is, but with Moxie... well. About Dragon/Fighting, that type would be insane and awesome. And the Pokémon with that type would go to Ubers right away unless given somewhat low stats, like 85 across the board. Another good typing is Electric/Fighting. Two weaknesses (Psychic/Ground), and five resistances (Bug, Dark, Electric, Rock, Steel), and huge offensive coverage especially if it has access to Ice-type attacks. BoltBeam AND a STAB Fighting move? Yes please. But yeah, I hope many new typings get introduced, and I hope some of those Pokémon are weak enough to use in NU if auto-weather stays in OU.