I personally feel that Deoxys EX (attack)/Metagross decks will be one of the few decks that can change gameplay significantly. Whereas old school Gardevoir EX will pose trouble as a main archetype deck with Boosts' return. The new Rayquaza EX may change the Blaziken/Rayquaza EX format. It is all a matter of opinion on this.
no matter what ppl say, dark draggy/dark trode is the best deck nowdays, just need to be well prepared for the metagame you're playing at, to make sure what you'll tecH
You know Draggy needs to Tech a Wobby now right? Yeh, Wobby. Draggy is still the best IMO, even with Satan having been reprinted. Fast setup only beaten by Zapdos in that respect, but with good stability.