So for those who don't know what this game-warping beast of a card does, here's the effect (prepare yourself):
At the end of the Battle Phase, if your opponent controls more cards than you do: Make your opponent banish cards they control face-down (their choice), so that they control the same number of cards as you. If you control no cards, you can activate this card from your hand.
Ikr? I think this card alone is going to warp the choice of going first or second, how people build their decks and what kind of plays people make in a duel. I want to talk about what changes to the game this card will bring and how we can counter it.
First the choice of going first or second. Considering this card is at its most powerful after your opponent invests most if not all of their resources into making a huge field, does the existence of this card make going second a genuinely viable choice? Or do you go first, make a reasonable but not all-in kind of field and save some combo bits so that if they choose to skip their M1 and BP to use SB straight away you can still come back from it, perhaps even use your own SB on your next turn? Do you choose to go second second to hope you draw SB but sacrifice the advantage of being able to go for your own combo vs a guaranteed empty field empty field considering you might not even draw SB (but you probably win if you do unless you're vs someone who is smart enough to respect it and not go all-in, maybe).
How about during the duel itself, what kind of decision do you make to adhere to the possibility of your opponent having this card? I'd be surprised if, once this card comes out in the TCG, people still just blindly go first and make all the firewall dragons they can. This card alone is going to force people to find a balance between making a threatening field and not over-committing to the point where SB will win the game. Obviously there are ways to make a field that can counter SB but I'll get into that soon. How about bluffs? If you won rock paper scissors and because of this card you choose to go second, how do you react if your opponent does nothing and just passes the turn to you? Do you believe they have SB and do a minimalist play or try call their potential bluff and punish them for leaving the field open? Obviously if you can do 8k damage that turn you're golden. What about the other way around. Your opponent lets you go first and you draw SB. Do you pass the turn without doing anything hoping to get a huge advantage with it and risk being OTK'd or do you make a field anyway and keep SB as a backup plan?
So, decks. Right now a couple of promising decks are spyrals and world chalice. They're decks that, with extensive combos, end up bringing out a lot of strong link monsters and kinda sorta hope that one field will win them the game, but are decks like that still as safe a choice for competitive play with this card being a thing? I know I pointed out that you can simply half-invest (if you will) so that SB doesn't end the game straight away but can these decks actually do something threatening without making 6 firewall dragons? Or will the necessity for come backs and resource management force slower, less explosive decks into the metagame that can afford to main deck this as they aren't desperate to draw combo pieces in their opening hand? Is it going to become necessary to main deck things like wiretap and/or artifact lancea? Does SB even belong in the side deck at all or should you sacrifice consistency so you can have a chance of opening with a card that has such devastating potential?
Lastly I'm going to point out some ways this can be countered. I've already mentioned a couple: Artifact lancea that you can tribute from your hand during either player's turn to prevent cards being banished for a turn and wiretap that is a counter trap that negates a trap card and shuffles it into the deck. There are some more possibilities too like tri-gate wizard, a link monster that, when co-linked with 3 other link monsters can negate any card or effect once per turn. There's also a cards like black garden and ojama trio that put tokens on your opponent's field that would reduce or entirely mitigate the effect SB has on your field. I don't think those are realistic choices though tbh, but time will tell. My knowledge of yugioh cards isn't all that great though and I'm sure others can come up with more and better cards to counter struggling battle.
One thing is for certain, while this card is around the game of yu-gi-oh is going to be played differently and decks may well be built differently just to adhere to it.
I apologise if this post is a somewhat incoherent jumble of excited ideas but I think there's enough here to get some interesting discussion and debates going. I look forward to hearing other people's ideas.