I was thinking today on how some NPC characters refer to the Afterlife as either 'The Light' or 'The Twisting Nether'.  Remembering that there is an energy-filled chasm called The Twisting Nether in Outland (which is another dimension separate from Azeroth), it made me wonder if Outland is the 'afterlife dimension' in WoW, with Nagrand perhaps being 'heaven' and the rest being H-E-double hockey sticks.  Or maybe Outland is just the closest physical point in the multiverse to those afterlife realms. 

If one falls into The Twisting Nether then they die and respawn, as I recall.   That would also suggest that you can't go to the WoW heaven / heck until you're dead for ever and not resurrected at a graveyard anymore.

Presumably, since people are respawned in the exact physical body that they had before death, the point of permanent death would come when one is so old that you would respawn and then immediately die from natural causes, so further attempts at respawning would be pointless and the player-ghosts decide that they may as well pass on to their eternal place of existence.

If a player can respawn at graveyards then why can't NPCs?  Why do they go to the Light / Nether, or become the undead?  It's like the angels at the graveyards have some 'fourth wall' knowledge that you are a person in the real world and will only dispense their regenerative favors to people from Earth.  

A famous web-comic with strong afterlife themes called 'Jack' tends to attract forum posters who discuss the philosophy of the story to the nth degree and sometimes flame-war with each other in disagreements.  One day the comic's creator got mad (I think he had toothache that day, which didn't help) and said "It's just a comic!!".