The visual indications of Lost Zone cards look neat, but my interest in the Lost Zone mechanic is… the mechanic. Now take this with a grain of salt because I have been out of the loop with the Trading Card Game for years now, and the fact that I have a strong opinion of a mechanic rather than collecting says a lot--but these just seem lackluster to me. Almost every card focuses on putting YOUR cards in there, and few make use of the cards that are in there. Like, you can aim for a free 110 damage with Cramorant, a single use 1HKO from Giratina VStar, or energy acceleration with Mirage Gate. ...But then what are you accelerating energy onto if Cramorant attacks for free and if Giratina makes use of the Lost Zone once? I guess attacking with Giratina VStar's regular attack? But if this is in any other deck, can you afford to put all the cards required to make use of that energy acceleration in your deck, on top of having 7 cards completely removed from play?
If these new cards are mainly going to focus on you sending cards to the Lost Zone in order to gain some sort of benefit, there needs to be a drawback for making use of the Lost Zone aside from cards simply being removed from play. As I was reading it, what I THOUGHT that Banette Ability was going to be was Once during your turn, you may choose a Supporter card from your Discard pile, reveal it, and use that Supporter card’s effect as this Ability, then place that Supporter card in the Lost Zone. If that’s too much of a broken Ability, it could go further by saying you cannot use more than one of this Ability per turn and/or if you do, put this Pokémon in the Lost Zone, like it already says. That would be a strong effect! But it has its drawbacks.
What I remember liking about the Lost Zone was that you had to use it to your advantage and to your opponent’s disadvantage. The only cards revealed here that disrupt your opponent are Lost City and Lost Sweeper. But unlike previous attacks that send KO'd Pokemon to the Lost Zone, Lost City doesn't include energy and Tools. And there doesn't seem to be any specifics for what you want to be in either your or your opponent's Lost Zones. There's nothing like Mew Prime, the Lost March Pokemon, or Raikou from Lost Thunder that uses those specific cards in your Lost Zone for a greater effect.
I guess what I'm trying to say is that I liked the variety that the Lost Zone previously brought. I'm looking forward to more cards being revealed, now that we've seen that Lost Zone binder with Rotom and Shiftry in the artwork. But right now, not considering the Expanded format, these cards get funneled into "Chuck 17% of your deck away, power up Giratina's single use attack, ???, profit!" But again, I've been out of the TCG for years now, maybe there are other uses for these cards that I'm not aware of.
I think you're missing the point that cards that might help you can also help the opponent and that you're losing ressources for advantage/power.
Lost City is a good example as are Giratinas attacks.
Your opponent might be using the Lost Zone too, which you power up with Lost City.
In the end you're trading ressources for card advantage and power. Since you can't just keep on returning certain cards to your deck over and over, energies gone are gone and not endlessly recycled (like they used to be during my TCG playing days). The same is true with other cards.
So you're forced to play more energies than you'd usally do. Which is not something you really want.
I'm really eager to see if they do more with it or if it's one of those "side-gimmicks" that get 1-3 set support and then are dropped totally like the fighting styles, Pokémon SP or BREAK and everything similar.