Resurrection: Having my cake and eating it too

Resurrection is a part of classic D&D that don't really love. 

For one, I don't like the gameplay implications. If resurrection is relatively easy, it devalues death. If it is somewhat hard, you get this weird situation where a player has to play a temporary character, or sit out one or more sessions, while the rest of the party tries to get their old character back. Both of these things might be non-issues for lots of folks, but it isn't something I enjoy happening at my table. 

Second, I don't like the worldbuilding implications. If resurrection is possible, it seems weird to me that powerful individuals or institutions haven't used it to gain even more power, using it on the regular or monopolising the single use item(s) that allow for it. Especially if you have elves and stuff in your games (or other very long living peoples), as there is no real reason for them to not have sought out these options. 

Moreover, on a deeper level I don't really like the implied metaphysics of resurrection. It seems to almost always suggest the existence of some sort of christian soul, which is the essence of what you really are and contains your personality, emotions and memories, leaving the body to be either merely a container for said soul, or an annoying filter interfering with it. This worldview bores me and as someone who has studied philosophy is hard for me to accept as consistent. 

On the other hand, resurrection gives the GM fun gameplay options. From recurring adversaries, to post mortem hostage situations. And I think you can create some really fun narratives with the 'they returned from the dead but are forever changed' trope. 

So with that in mind, here is a suggestion for having resurrection without having resurrection:

It is impossible to resurrect a person. However, it is possible to have a demon posses a dead person's body. When the demon is cunning and has had a chance to observe the deceased during their life, they are able to do a very convincing imitation of the deceased person. Which is why some belief resurrection to be possible and why people continue to attempt it. 

This fixes all my problems with resurrection and allows me to have the bits I like.