Metagross would be good...but that leaves me with 3 Fire weaknesses, two resists and a pokémon that, if it survives beyond its' initial outing, will be OHKOd by anything it isn't immune to.
What would I swap Gyarados for? Dragonite can't really afford to go...it's the most successful pokémon out of all of them overall - the others work in Trick Room, but other than speed hindering it, Dragonite wrecks people who get cocky.
EDIT: Dragon Dance kinda fails in Trick Room - the attack boost is nice, but the speed isn't.