When judging a card's impact on the current meta, one must acknowledge the competition such a card possesses, and whether that makes this card stronger or weaker.
Yveltal is prominent in both expanded and standard; potentially a huge threat for this card.
Stacking up energy via manual attachment will cause you to be hit multiple times for (possibly) free damage.
You have no way to OHKO an Yveltal("small")+Belt, so when you take out an EX, they could hit you with two Oblivion Wings. It just outpaces the deck, as there's not really a consistent way to ramp into three Psychic energy.
Greninja BREAK is also a huge threat to this card.
Free retreats to break poison, potentially running Max Potions, and the ability to knock out your Mareanies with Giant Water Shuriken as you attempt to ramp with Elixirs.
Yes, you can shut this down with Garbodor, but... Greninja's biggest weakness is usually just... not getting the right cards, and being too slow.
If you're running Toxapex/Garbodor, you're probably not running much else.
Your deck will be slow, and the possibility of Greninja finding an answer to Garbodor before you set up, is quite high. You both need to evolve, and you both need energy, but the Greninja deck is entirely focused around that.
Also, take into consideration the Psychic Weakness, leaving this card extremely weak to both M Mewtwo, and M Gardevoir.
Conclusion: I can see this card being used, but I don't expect it to be a huge threat in the competitive scene; especially since the majority of decks have started running a copy of Pokemon Center Lady.
Grade -- Silver
(On a scale of : X - Bronze - Silver - Gold)