I've messing with a modest/rash (+sp.atk/-sp.d) draco plate hydregion, with earthquake or eath power for heatran. It doing just a lot better then I excepted. Draco plate bluffs specs really well and I feel one of hydregion's main selling points as great pokemon is his excellent move pool coverage with just wanting to hit really hard. Not getting pursuit traped like latios, is always a plus. The only dragon you want/can to be outspeeding is haxorus, and he's normally adamant.
So I'm really evil apparently