I don't think there is a "should" when it comes to specific ways of handling death, especially its story impact, in D&D. We tell different tales in different settings, and despite many shared assumptions this one is so big that it deserves its own space in the game.
The only should I see, therefore, is for providing these abilities as an interface to the various ways one can imagine handling death and resurrection. That creates common means to access similar effects, and handling interaction with other game elements, without presuming to set down a cosmology.
There are so many different ways to think about it. Sometimes an exploration of societal impact of easy resurrection for the rich isn't a distraction, it is part of the setting (this is fodder for a lot of sci-fi stories, and I'd guess plenty of fantasy as well). Maybe resurrection has consequences, ranging from the inconsequential, to the bizarre, to the dangerous. Maybe there are consequences not necessarily for the resurrected person, but for the person performing the resurrection. Maybe Raise Dead is closer to a phone call to a dead soul, but in some cases giving it a temporary "spiritual body." Maybe Raise Dead is cast on the living, a sort of Astral Projection where they actually venture into the afterlife to bring a lost soul back, and that process isn't necessarily without conflict or danger to the living. Maybe the deities each handle it in their own way, so a deity of fate might grant life for "one final task" while a deity of life might grant a new life without strings attached. Maybe there is a prophecy of a "second-life" for all creatures at the passing of the original creation, and to obtain that second life now is to risk one's entire spiritual reward should death (this time oblivion) occur again before the final victory is won. Maybe the souls of the dead are the raw matter in creating a new creation, and resurrection actually prevents them from passing to this new land, forced to remain in life or death as an inhabitant or guardian of the old world. Maybe death is a process of annealing a soul, to be repeated many times until ready for some task one with only mortal eyes could not see. Maybe reincarnation is the setting's norm, and raise dead is a way to hijack that process, but only if the timing is precise (and if not there may be significant "leaking" from past lives assuming the effect works at all). Maybe reincarnation is the norm, but a final death is actually valuable because only in that state the soul retains the knowledge of all past lives, in which case "raising" a person actually puts them into the final death where all their past lives are finally accessible to them, essentially raising (in a spiritual sense) beings that have been dead for eons. Maybe there is only oblivion. And maybe there is only oblivion, but this is hardly common knowledge, and the spirits which inhabit "raised" bodies prefer to keep it that way.
That's hardly scratching the surface. Give DMs the tools they need to run the kind of game they want, and if they want to handwave the whole thing (easy resurrection for PCs, hard for everyone else for no particular reason) then make that an option as well.
The only should I see, therefore, is for providing these abilities as an interface to the various ways one can imagine handling death and resurrection. That creates common means to access similar effects, and handling interaction with other game elements, without presuming to set down a cosmology.
There are so many different ways to think about it. Sometimes an exploration of societal impact of easy resurrection for the rich isn't a distraction, it is part of the setting (this is fodder for a lot of sci-fi stories, and I'd guess plenty of fantasy as well). Maybe resurrection has consequences, ranging from the inconsequential, to the bizarre, to the dangerous. Maybe there are consequences not necessarily for the resurrected person, but for the person performing the resurrection. Maybe Raise Dead is closer to a phone call to a dead soul, but in some cases giving it a temporary "spiritual body." Maybe Raise Dead is cast on the living, a sort of Astral Projection where they actually venture into the afterlife to bring a lost soul back, and that process isn't necessarily without conflict or danger to the living. Maybe the deities each handle it in their own way, so a deity of fate might grant life for "one final task" while a deity of life might grant a new life without strings attached. Maybe there is a prophecy of a "second-life" for all creatures at the passing of the original creation, and to obtain that second life now is to risk one's entire spiritual reward should death (this time oblivion) occur again before the final victory is won. Maybe the souls of the dead are the raw matter in creating a new creation, and resurrection actually prevents them from passing to this new land, forced to remain in life or death as an inhabitant or guardian of the old world. Maybe death is a process of annealing a soul, to be repeated many times until ready for some task one with only mortal eyes could not see. Maybe reincarnation is the setting's norm, and raise dead is a way to hijack that process, but only if the timing is precise (and if not there may be significant "leaking" from past lives assuming the effect works at all). Maybe reincarnation is the norm, but a final death is actually valuable because only in that state the soul retains the knowledge of all past lives, in which case "raising" a person actually puts them into the final death where all their past lives are finally accessible to them, essentially raising (in a spiritual sense) beings that have been dead for eons. Maybe there is only oblivion. And maybe there is only oblivion, but this is hardly common knowledge, and the spirits which inhabit "raised" bodies prefer to keep it that way.
That's hardly scratching the surface. Give DMs the tools they need to run the kind of game they want, and if they want to handwave the whole thing (easy resurrection for PCs, hard for everyone else for no particular reason) then make that an option as well.