if there is ever a deluxe edition for the Berserk issues made after Miura's death— do you think they should keep the same trade dress or change it aesthetically in some way to show his absence? Lot of ways it could go.
My honest thoughts are that it should be packaged exactly the same, just with the appropriate crediting for "Original story/design" to Miura and "art/script" to Studio Gaga and Kouji Mori respectively, along with a foreword to the first volume collecting chapter 365 onwards that clarifies that what follows is the story as recalled by Mori from notes given by Miura. While it makes a great deal of sense to draw a sharp line between what was written before and after Miura's passing, I don't think it shows sufficient respect to the trust placed in Mori by Miura in sharing his full vision for the manga with him OR to Gaga's collective efforts to continue their teacher's work to cut it off too harshly.
There will always be people for whom Berserk ends at 364 - in a sense, i'm with them, but I want to see what the broad strokes of Miura's intent were, and I feel like his lifelong friend and his students are the best people to deliver that, even if I feel like the chapters released by them so far are rather perfunctory and I don't have a clear handle on their full potential yet. I think for a lot of people Berserk honestly ends sometime around the conclusion of the Conviction Arc (which I don't think you've read yet) which was like a decade plus before Miura's passing but represented a full and complete narrative "cycle" in many ways. I can see a world where we consider Berserk a "complete" work that has several supplemental arc/cycles that elaborate on themes from the story and do indeed have some phenomenal moments in them that easily match Golden Age, but which aren't strictly necessary to fully process Berserk's core concepts or the value of the work overall, warts and all. I say this with the qualifying note that for me personally I think several of Miura's greatest ever moments are specifically beyond that "end point", but understanding Berserk as "complete" allows those moments to exist independent of the endless susurrus of theorycrafting and desperate need for a "Proper" ending.
I'm excited to read whatever Gaga and Mori put out, and to respect it as a manuscript detailing Miura's wishes. Guts says of his prosthetic arm at one point - "I forgot" when he tries to grasp something with it as he would a flesh and blood hand. "Even if you force something back into the same shape... it's still different". But that arm still serves, and it represents a desire to be whole again.