Isometric action RPGs often use fully fixed camera perspectives, a design element dating all the way back to Diablo and other classic isometric games. The fixed perspective gives the development team exact parameters to craft every other piece of the game around. When you know what area the player can look at during all moments of play, it directly impacts level design, enemy behavior, and effective attack range, among many other aspects of gameplay. It sets the ground rules around which all the other game design elements flow.
Diablo IV has a strangely, aggressively zoomed-in camera — both for the genre and for the franchise. Diablo I, II and III all offer much wider perspectives on the action at all times. The camera in IV presents a tight and narrow view for the majority of its playtime, zooming out a tiny bit while you’re on a horse, and zooming out to a wider view during the limited and optional world boss encounters.
I think this creative choice was super bad for the overall game design, and it’s also quite at odds with the idea of a large open world — present in Diablo IV for the first time in franchise history. You only ever see a small bit of this world, and as such it’s limited in scope even in those rare moments…
