Master Ball's plenty good early game :/
But T2 Vibrava isn't that impressive, no. Sure, it's laying a damage counter on everything. Do you... Actually have the resources to take multiple prizes in a turn? Not... Really... (MAYBE Flygon EX d can. MAYBE Lucario can. It still takes a ton of effort, with the BIG HP pokemon that we have running around nowadays).
Flygon's also got 120 HP and no fighting resistance, meaning Gallade can either flip 3 prizes to slaughter it, or just Sonic Blade then not have to flip ANYTHING to kill it. Ow.
That's the main problem, actually. You just don't hold an answer to Gallade, EVEN WITH FLYGON EX d. Flygon EX d winds up being un-OHKO-able, true. But it also gets Sonic Bladed to death (which is VERY VERY VERY bad on a 150 HP stage 2 EX).
Need an answer to the silly pokemon who ruins your set up, is immune to Flygon SW's body, and is so easy to send early game (with the Gardevoir SW to help it, of course). Darkwing duck isn't the problem if you use Crystal Shard or another cool tech to eliminate your fighting type. Gallade is.