As of right now, I can imagine that these decks will win states.
Gyarados
Cursegar/Spiritomb
Luxchomp
These three decks are currently the decks that really shine at this very moment. I'll explain why each would have the most potential.
1. Gyarados- Although not really #1, Gyarados has really seen some success lately, and will likely see lots of play in states. It can be a very effective early game attacker, as well as mid-game and late game. It has very useful ways of recovery, mainly Combee SF and Pokemon Rescue. With Expert Belt, Gyarados can now One-shot Luxray GL, and it Luxray were to have expert belts, it has either Pluspowers or Crobat G for backup to do more damage. It can even utilize cards like Regice to get through Spiritomb or Mr. Mime MT, as well as discard Magikarps. That's where the second concept comes in. The big strategy of this deck is often to discard 3 magikarps to the discard pile, and have 1 to go to Gyarados. Once you manage to fully do so, you bring Gyarados to do 90, or 110 of there's expert belt. Further more, no energy is needed for the attack. Gyarados also easily goes through Donphan, so the only matchup I imagine it suffers is just Cursegar. Otherwise, everything else it does pretty well against other decks, so I won't be surprised if it wins lots of states.
2. Cursegar/ Spiritomb- Although a bit slow, it seen lots of play in the Benelux Cup. That's because currently, it is the best decks to utilize Spiritomb, better than even Glistomb and Magnezone/Spiritomb. The strategy is simple. Use Gengar Ar's Shadow Skip to do 60, and then switch to Spiritomb to trainer lock. Repeat this for several turns and this can really lock or oopponent from using trainers. Futher more, it can take advantage of Gengar SF and Gengar Lv. X to bring more potential. It easily takes down GG, as well as some SP decks, and even Gyarados, despite Regice goes through Spiritombs. Because of this, I also won't be surprised if this deck will win a lot.
3. Luxchomp- Currently the most dominate SP deck. The deck utilizes Luxray GL to take down important pokemon like Claydol, and Garchomp C to heal and also hit, mainly on the bench. Now with DCE, Luxchomp has pretty much become the best SP deck to use DCE. DCE allows Luxray to be given some speed without energy gain, and thus it takes good use of Expert Belt, meaning it can do either 70 or 90 most of the time, making it far more dangerous. Garchomp also loves it because this means Dragon Rushing is way to easy, and it can do so for almost 1 energy. With many techs to aid the attackers, it virtually does well against many matchups, not counting machamp. It came first place several times in the Benelux Cup, so it is no wonder this deck is having success.
So these three decks will likely have the highest ratio of winning states. Of course other will be played, but I can imagine that Gyarados, Cursegar, and Luxchomp will most likely be winning the most states.