Alrighty then. GameFreak has officially released the new type matchups (quite a while ago, actually): http://www.pokemonxy.com/_ui/img/_en/art/Type-Matchup_chart_EN.pdf
Based on the new Fairy matchups, the use of Dragon moves will vary intensely due to the new immunity. Offensive Steel and Poison moves may increase for a while, but I believe that in all metas, especially BH, there will be a huge bang of fairy and anti-fairy presence due to the new type matchups, but it will diminish into a new but balanced metagame, just like today. It might encourage Poison/Steel offense for a while, but will lessen over time. A longer lasting effect, will be that the infamous Dragon/Fire combo will indeed have Pokémon that actually resist it (yes, I know about Heatran, but that relies on its ability) such as Marill and Fairy/WhateverResistsFire types.
Based on the new Fairy matchups, the use of Dragon moves will vary intensely due to the new immunity. Offensive Steel and Poison moves may increase for a while, but I believe that in all metas, especially BH, there will be a huge bang of fairy and anti-fairy presence due to the new type matchups, but it will diminish into a new but balanced metagame, just like today. It might encourage Poison/Steel offense for a while, but will lessen over time. A longer lasting effect, will be that the infamous Dragon/Fire combo will indeed have Pokémon that actually resist it (yes, I know about Heatran, but that relies on its ability) such as Marill and Fairy/WhateverResistsFire types.