You may be right. You may be wrong. What I know is that Pokémon is a game where the Bench is meant to be "safer" and not "safe", or at least I suspect as much based on the game's history. Giving up an Item just to force the opposing Pokémon of your choice upfront isn't that powerful on its own. Why was Gust of Wind nicknamed "Gust of Win" if it wasn't powerful? Because it wasn't on its own: like now you had decks that were donk enabled but not built only to donk.
So reading through the rest, I've got to ask - what decks does a lack of Pokémon Catcher jump to tournament viable? Most brought up earlier were not persuasive as I've already elaborated upon. What decks suddenly take a significant plunge?
It's not necessarily a lack of Catcher that makes more decks good. It's that combined with the new Silver Bangle and Silver Mirror tools.
Suddenly a Garchomp/Altaria deck can hold Altarias on the Bench, meaning with three Altaria its second attack + Silver Bangle will OHKO anything. This is a better deal than using EX attackers because Garchomp will only give up one Prize so it's less likely to lose Prize exchanges. Sure, between Genesect, Ninetales, and Escape Rope, my deck might lose one or maybe even two Altaria over the course of a game, but keep in mind that Gabite can help get them back and even with only two Altaria in play I still OHKO most cards.
Similarly, a Chandelure deck could be viable because it's no longer impossible to set up more than one Stage 2 consistently. Yes, Genesect and Ninetales are problems, but they also keep the game healthy by preventing broken combos that others have mentioned from becoming too broken. As you say they are substitutes rather than equals, though, so they won't be able to completely break my setup and they won't even be used in every matchup. Chandelure has many attackers it can be combined with, including Reshiram PLF as a good Basic attacker or Infernape as a low-Energy attacker or Heatmor as a late-game finisher (come close to decking yourself then use Super Rod to put back a lot of Fire Energy) or Charizard + Silver Bangle as a power attacker to OHKO everything. Even Rayquaza-EX could be used if you felt you could set up enough Chandelure to make that viable.
Hydreigon decks could become powerful once again because Blend Energy combos with Virizion-EX and with Silver Bangle, Hydreigon OHKOs most EX cards. Of course, the deck takes a hit without Dark Patch or Sableye but it could probably find a way to manage. For example, it could use cheap attackers like Virizion-EX and Absol until the late-game, when it would shift over to Hydreigon or Darkrai-EX.
Empoleon can now set up multiple copies of itself with more ease, allowing for it to be a deck again. Empoleon/Terrakion, Empoleon/Dusknoir, and Empoleon/Ninetales could all be viable and some of these could even be used in combination with each other. A version of Empoleon could even be made with attackers that counter the metagame like Haxorus and Garchomp. No, Empoleon isn't as powerful as the other decks I mentioned, but it has great card advantage and makes better use of Catcher alternatives and format counters than most decks do. In a format with Catcher, Empoleon/Dusknoir would never work because Dusknoir would get Catchered and Empoleon/Ninetales would be stupid because there's Catcher.
Reuniclus decks could exist alongside Plasma Tornadus-EX, Eviolite, and Aspertia City Gym, or even alongside Wailord and Giant Cape. Mr. Mime helps solve the problem of Solosis' low HP and it's a lot harder to take out Reuniclus with the Catcher alternatives available to most decks.
Shedinja could be half-decent alongside Rescue Scarf and Plasma Darkrai or another switching Pokemon. The damage output would be lacking but between Rescue Scarf, Super Rod, and maybe even Ninjask, the deck could possibly hold enough Shedinja in play to win games.
Ampharos could be a decent counter to Blastoise; between it and Frozen City a Keldeo or Black Kyurem that wants to OHKO the Ampharos would get KO'd just trying to get enough Energy attached to make that possible. Yes, it's relatively easy to counter with a Stadium or Escape Rope and it's not very good against most other decks, but it's a cool idea that would have virtually zero chance of working in a format with Catcher... for more than one reason.
Counter cards like Sigilyph, Suicune, and even Ampharos could also be made use of in a format with less ways to switch the opponent out of the Active position. Double Suicune deals with Escape Rope. Genesect and Ninetales again come in to make sure these counter cards don't become too broken, although at a certain point they'll just run out of Plasma Energy or Devolution Spray. That's what happened with Luxray LV. X decks against Mewtwo LV. X back in the day.
Also, set up and support Pokemon could become semi-viable again. In a deck where I already have Stage 2 cards, a 1-0-1 line of Magnezone wouldn't be terrible because if I drop Magnemite on the right turn, my opponent probably won't be able to use their Catcher alternatives effectively right at that turn. Then after I get Magnezone, it's a lot harder to KO, so I can hope that they will choose to focus on other more immediate threats. Even if they don't, they've now wasted many resources to KO a tech of mine that's not integral to my main strategy. Catcher is just one card but Ninetales and Genesect are many cards that have additional effects (not being able to attach for turn, not being able to use the next turn without Devolution Spray).
The same could be applied to cards like Electrode and Clefable; they could actually be used to set decks up and draw cards although their effects aren't necessarily good enough to do so in most decks. Roserade, on the other hand, might actually be good alongside Ninetales and Devolution Spray. Even Jirachi-EX could be viable as a consistency tech since there would be less ways to abuse its low HP.
Also keep in mind that the Dragons-on format gets rid of all our old search except Ultra Ball and Plasma Ball plus it gets rid of N and maybe Tropical Beach. This means decks can't be as consistent as they are now and could encourage cards like Durant, Shaymin, Manaphy, and Emolga to be used as starters for setup. At first, it seems like fast decks like Plasma would run through these cards, but now we have Silver Mirror. And it can't just be Catchered around either; Tool Scrapper or Escape Rope has to be used. The former is hard to justify in high counts in a speed deck while the latter can be dealt with by attaching two Silver Mirror. Sure, there's still Landorus-EX, but it's not well-positioned for a late-game, especially in a format with Blastoise, Keldeo-EX, and Plasma Kyurem.
And then on top of all this, there's still the decks we have now. Blastoise decks still exist but they're made a lot worse by the fact that many non-EX cards can OHKO its EXs. Yes, it also gets better because Blastoise can't be "Catchered" as easily but testing reveals that Garchomp decks, Trubbish/Sigilyph decks, and many other non-EX based decks have favorable matchups against it.
And then there's the Trubbish/Sigilyph/Masquerain deck, which would be good anyway, but is yet another deck that could be pushed above the abyss of the lower tiers by the fact that the opponent is unlikely to be able to Catcher more than one Sigilyph with 4 Tools in a game.
Plasma decks would still be good because they're fast and make decent use of Genesect but wouldn't be broken because of Drifblim and Silver Mirror.
Garbodor decks would stay good. Landorus and Big Basic decks would get better because it's a fast card in a relatively slow format but would also be a lot worse because Landorus's first attack is nowhere near as good as it was with Catcher.
Darkrai decks would fall apart completely without Dark Patch but that's okay since we're bound to lose some decks with rotation. Of course Gothitelle and Eelektrik couldn't be used anymore as well.
Klinklang would get better because an EX-centered deck would have a lot of trouble against it, but would remain balanced in a format with a lot of non-EX attackers and no Shift Gear Klinklang.
Now, to be fair, much of this is theorymon but I have actually done some testing in a Dragons-on format since I'm not going to Nationals.
Your analysis if Genesect EX obviously differs from my own, but I wonder if it is because you are mistaking "substitute" for "equal". Yes, a deck will have to burn more resources to "Gust" something out through its Ability, but the decks that will use it... will use it. A Team Plasma deck built around the usual suspects (Thundurus EX, Kyurem [Plasma], and Deoxys EX) won't be able to pull of the counters they current do in a single turn... but two turns will do it, and with Pokémon Catcher gone they have that time.
I think this is the other foundational point that might explain our differing takes on the situation: remember with Pokémon Catcher gone, its gone for everyone. The Pokémon Catcher substitutes won't be as good, but they will be there for the critical game winning plays... which favor the "powah playah" decks we've got now.
Yeah, I understand that Genesect works even if it's not as good as Catcher. I hope I didn't ever sound like I was calling the card bad. Rather, I'm pointing out that many decks simply won't use it, or Ninetales for that matter.
Why? Because of space. Genesect and Ninetales take up at about twice as much space as Catcher did when applying for pre-evolutions, Devolution Spray, and/or Plasma Energy and yet they're not as good as Catcher. Especially in a format with more evolutions, it's very hard to justify such cards in every or even most decks.
For example, in past formats, we didn't see Luxray GL LV. X in most decks. For the most part it stuck to SP decks although there were exceptions (the worlds winning Beedrill deck). However, it was a Catcher alternative, so to speak. And the fact that it had a good attack and good support in Poke Turn provided even more reasons to run it.
We're already seeing many decks like Blastoise, Eelektrik, Klinklang, and Gothitelle drop down to 2-3 Catcher because of space and because they don't need it that much, so they'll have even more trouble justifying giving up even more space for even less effect. Of course Plasma decks would use Genesect and I'm sure we'd see creative uses of Genesect, Ninetales, and other cards like Dusknoir but that doesn't mean that they'll be in every deck or that they'll make other potential decks unplayable.
Again really sorry about the wall of text. I tend to get overly excited when talking about card design and stuff, haha.
