Because it's not and doesn't have to be. It's better because it's actually rooted in the source material and isn't just the character being splayed in some completely new, arbitrary way that has no canonical or fan significance. Alt costumes aren't relegated to just being "sexy/silly" - any appearance of any character is fan service material. The more significant or exclusive the better. That's what actual fan service is and always was, before it just become a code word for wank material to gamers online in the last 10 years who just want to see characters no one cares about dressed up in lingerie.
You seen the new Star Wars movie? Remember early in the movie when John Boyega was still in his Storm Trooper attire? Remember when he had a bloody hand print on his mask for just a few moments? Boom. Variant costume. 100% additional fan service potential.
If they did recreate that scene and created the character model and skin for it, why wouldn't it also be a playable alt? Alternatively, if someone had to choose between the two things, why not spend resources on stuff that's directly linked to playable content?
Why would anyone want to see that scene recreated if just the costume is too much? Especially in a game archetype that's become so attractive a fan service vessel for any ip that can be thrown at it, precisely because they can just include as many an ip's characters and plot points as possible into the same pot, with no real expectation of cinematic flair, masterful storytelling etc.
I understand that if the model is in the game for story purposes, they may as well use it as an alt anyway. Like, idk, Old Snake in his nice suit in MGS4. But this is being used as an incentive to preorder and boost sales. I think people uninitiated with Berserk are gonna see that promo image and think "Hey, tan anime chick in wet tshirt, hi-five brah", while those who see it and understand the context might think "Oh, that's from that scene. That was a really bad time for everyone. Why would I want to play as Caska in that, I'm just gonna think of all the horrible things that happened to her?"
I honestly don't think there's anything wrong with the promo image and pose itself, I mean it's a shot remake of the actual scene in the manga. Maybe would be better if it had the cave backdrop so people would understand it better.
And I don't think this would have been as bad if it was included in the game but not advertised or be a bonus. Like, here are your character skin selects, all of the variants used throughout the game, you can use.
Anyway I'm not gonna go on a moral crusade over this, Temco can do what they like and smarter people than myself can make better cases against them.
I do think naked Griffith armed with bucket of water should totes be an alt tho
Why would anyone want to see that scene recreated if just the costume is too much? Especially in a game archetype that's become so attractive a fan service vessel for any ip that can be thrown at it, precisely because they can just include as many an ip's characters and plot points as possible into the same pot, with no real expectation of cinematic flair, masterful storytelling etc.
If they're gonna do an adaption of that part of the story, I think it's kinda important they don't exclude that, it's pretty pivotal to showing why Caska is how she is now.
Or they could just do a text scrawl on how everything is fucked now after the Eclipse and then show Guts in his Black Swordsman rampage, but I think that'll be a disappointment to almost everyone.
Also to go with the Star Wars thing, how about Uncle Owen and Aunt Beru figures