Judging in YOUR meta, I've seen Luxcomp simply own G'dos.
But then again... I wasn't over there with the Masters during Regionals :/
Johnny was tearing them up, man!
It's simple. RESOURCES!
Luxray needs a basic, a Lv X, Lucario GL, a Crobat drop, an Energy, and an Energy Gain (or 2nd Energy). Or, 2 Energy, Gain, Lucario, and an Energy discard with Trash Bolt.
If the Gyarados is belted, they HAVE to use Trash Bolt and a Crobat drop to OHKO the thing.
Gyarados is almost guarenteed to OHKO a Luxray from the point they have 3 Karps discarded, onward, and they only require a basic, a Stage 1, and 1 or 2 of their MANY damage boosters (or none atall if it isn't Level'd up).
Not only that, but a 2-2 Lux means JUST THAT. They only have 2 Luxrays! Most SP's will only run 2 recovery cards: 1 Aaron's and 1 Night Maintenance. They have to constantly recover from the OHKO's the Gyarados is dealing them, while also spending a LOT of resources to OHKO them back.
Last but not least, Gyarados is pretty much unaffected by Luxchomp's disruption, as while they have a few bench sitters, none of them are neccessary for the deck to function.