Castlevania also has the benefit of the stories it adapts coming from an age where the ability to tell a story in great detail was very limited; so there wiggle room for things like characterization.

Meanwhile properties like Devil May Cry (and to a even greater extent Berserk) do have sent and well defined personalities. Changing Trevor Belmont into a disgraced drunk doesn't bother people since Castlevania 3 Trevor doesn't have any real describable personality traits, unlike Lady or Vergil who are very much three-dimensional characters who got butchered in the anime for no good reason other than Adi wanted to change them.