Derren said:
The real differences would be in politics and warefare.
No, the real differences are so vast as to be incomprehensible.
The "destiny" (or "most people just don't come back") explanation actually preserves verisimilitude for anyone who's willing to take more than a surface look at what the possibility of raising the dead would change about society.
D&D's four levels of dead is twice as many as exist in
The Princess Bride, which, I feel the need to point out, is a comedy.
1) "Fortunately, your friend here is only dead. We should be able to bring him back, but he'll be weak for a while." (Raise Dead)
2) "Sorry, your friend's not just dead, he's very dead. That spell we used last time won't cut it - you need a more powerful spell to bring him back." (Resurrection)
3) "Oooo...your friend's not just very dead, he's extremely dead. Oooo...that's gonna cost ya." (True Resurrection)
4) "Sorry. He's all dead. Guess all we can do is go through his pockets and look for loose change." (And this really is what most people call "dead.")
Even Billy Crystal couldn't make this funny.
It changes politics, war, inheritance law, economics, the social order, religion, and I can't even imagine what else. Trying to apply logic to fantasy is, IMO, a mostly fruitless exercise.