That's a good point actually.The biggest problem I see with this deck idea is just the sheer energy cost of Gyarados. It makes it very vulnerable to Gardy, and I really think that's going to be the measuring stick for good decks. That said I would like to see a Gyarados GX and baby Gyarados deck and see how that works. Gyarados/ Gyarados/ Garb could be good as well.
Against gardy, it may suck. But there is still a CHANCE you can beat them, especially with some good techs like XY67 Jirachi for instance. With Choice Band it hits Garde fir 80 and discards one of their special energies which is going to be very good against garde. Against everything else, Aqua Patch or Max Elixir + just your regular attachments should be able to power your way to the end. Metagross gets destroyed by Gyarados, Volc is 50/50, and Darkrai is maybe like 60/40 in your favor. There are plenty of other threats but those are the big ones.
youre the faster of the 2 decks, and you both 2HKO so you'll probably win.I fail to see how Gyarados gx destorys Metagross... It misses the one shot by 20, so unless you can string Kukuis...
Your set up and damage would revolve around Palkia EX, Gyrados GX, Max Elixir, Float Stone, Brooklet Hill, and Lusamine.
Paklia EX can help speed things up in terms of energy early on in the game, Max Elixir to accelerate Palkia EX when you don't start it or to accelerate your Magikarps before you evolve up.
Brooklet Hill and 2 Lusamine for very obvious reasons, then Float Stone to just get undesireable actives out of the active.
I think it'll be a little too clunky, but maybe it would be good for fun.
youre the faster of the 2 decks, and you both 2HKO so you'll probably win.