Game Freak was already starting to nerf Special moves in Gen 6 with the nerf to Hydro Pump, Fire Blast, Blizzard, Thunder, Hurricane, Draco Meteor, Leaf Storm, Overheat, Aura Sphere (-10 base power to all), Thunderbolt, Ice Beam, Flamethrower, and Dragon Pulse (-5 base power to all). It's sort of a mystery to me why they didn't nerf Focus Blast, but I'm guessing that's because it doesn't have the "perfect accuracy in *insert weather here*" effect that Blizzard, Thunder, and Hurricane do. Focus Blast was actually pretty equal compared to Fire Blast and Hydro Pump, except that Hydro Pump got the short end of the stick by not having a secondary effect.