I'm going to Dallas, here's my take on it.
Between the end of San Jose and Dallas, no new cards will be released. So whatever is good in San Jose, will be good in Dallas. Albeit, with a bit more refinement.
ZOROARK VARIANTS - I'm seeing 4 big ones in San Jose: Golisopod, Lycanroc, Night March, and straight Zoroark. From what I've been reading, Golisopod is the weakest, Straight is the strongest and most consistent, but Lycanroc has a better matchup spread. I honestly think that the Golisopod variant will not be seen as much in Dallas as San Jose. I'm not sure what to think of Night March, Lycanroc or Straight Zoroark as I can see their popularity go either way. A LOT of it comes down to which top players pilot which version. That said, I DOUBT any fighting deck is going to come out of the woodwork to take it on in Dallas. You have Carbink Break decks (which haven't gained a whole lot since their top 32 appearance in Fort Wayne). It's not an easy deck to pilot and absolutely dies to Garb-Necrozma Toolbox. That said, Zoroark variants are here to stay. I feel like I should update this part after San Jose.
GARB-NECROZMA TOOLBOX - Zoroark variants give the deck a hard time. I mean, so does Trevenant, but that's a whole nother can of worms. Yes, the deck DID win Daytona regionals, but I think that's honestly the best the deck can get. It doesn't gain much of anything, or at all, from Shining Legends or Crimson Invasion. There's not really much you can sub out for anything else. I think that the versions we see at San Jose are going to be the same for Dallas. The deck might use some different Pokemon techs, but that's all I'm seeing. It's a bit like the Sky Field Turbo Darkrai variants in terms of how the deck staunchly wants to stay the way it is for the best results. Zoroark will knock it down a few pegs, but it has decent matchups against most everything else.
GARDEVOIR - Gardevoir will continue to be a top contender. The problem it has is that it literally cannot tech for everything. So whatever it doesn't tech for has a good to favorable matchup against it. That said, there is no silver bullet to Gardevoir. I don't think we are going to see any radical change with any Gardevoir builds.
NIGHT MARCH - Everyone is teching for it these days. We now have 2 versions. Those that use Zoroark GX and versions that don't. The big difference is that the Zoroark versions completely get around their silver bullet counters: Karen and Oricorio. I think because of this, Karen is going to be used A LOT less and Oricirio will be seen more as the more splashable tech. I think the most successful versions of Night March will be ones that include Zoroark GX. Specifically, a 2-2 line of Zoroark GX, as prizing one of the components in a version with 1-1 leaves you open to Karen and Oricorio plays.
DARKRAI EX/DARKRAI GX - I think that Darkrai EX/Turbo Darkrai is outdated. It's one of the most consistent deck of the format and it's not as good as it used to be. The Darkrai GX version has a slightly better match spread. At least, it does more favorably in matchups its already good in.
SABLEYE-GARBODOR - This is one of the best decks in the format. And unfortunately for it, people know it. It's a deck where if more people are expecting it, the worse it does. Zoroark CAN give it a hard time, but it all depends on how the Zoroark deck is constructed with support trainers and whatnot. I think San Jose is going to have a bunch of Ghetsis in decks in anticipation of it, but may not be necessary. Thing is, the deck has a high skill floor and ceiling. So unless they are going to make it their pet deck and work with it from the end of San Jose to Dallas NON STOP, or they have a good knowledge of how it works and how to read into other decks for threats and predictions: don't run it. I feel a lot of people who pick up the deck are going to do terribly with it and I think that's going to happen in San Jose. Not so much for Dallas. It'll be a contender in Dallas. But only in good hands.
TREVENANT - Call me crazy, but despite the surge of Zoroark decks, I see Trev making a comeback like it did in Daytona. The massive ammount of Zoroarks in the field in San Jose will have people writing it off. That's all I'm going on is that I think San Jose is going to make everyone drop their guard. Thats what Trevenant decks count on.
GOLISOPOD VARIANTS - Still a contender, but I don't think they are going to reach top 8. Bunch of variants: Toad, Garb, Zoroark are the big ones. IT's a good deck, but even as I'm typing this, I don't see many Golisopod in top 32 in Dallas. I honestly think that something innovative has to happen for Golisopod to see good results this time around. Golisopod-Fighting. I don't know.
TOAD-SERVIPER - I was under the impression that this was a 'surprise' deck and everyone would be able to tech for it and shut it out. Not so much. It is unfavorable against Gardevoir (provided they run Comfey), Trev, and Zoroark variants. Sort of a weird set of things to be unfavorable against. This is a deck where, unless you know how to tackle it, it'll destroy you. I don't think this'll top 32.
VOLCANION/TURBO TURTLES - Easy to run decks that are good at what they do, however with the lack of Golisopod--or at least the massive saturation of it that we saw in Fort Wayne, the deck doesn't have the ability to sweep D1 as easily. That and the fact that they have terrible matchups against T1 anything. They can go toe to toe against tier-2 and rogue stuff very nicely. But as soon as they start racking wins from there and go up in tables, they're going to get knocked back down to lower tables again.