Well, Gandalf, it's nice to see you again, but...

[davem]

I'm not sure Tolkien ever intended that Gandalf should die in Moria. Clearly we (as the Fellowship) are meant to think he died, but from my reading of HoM-e I can't see any point at which Tolkien thought that he had killed him off & then changed his mind. He even puzzles over how to account convincingly for his reappearance: 'How does Gandalf reappear?' (The Story Foreseen from Moria, HoM-e vol 7). Also Vol 6 'The Mines of Moria:

(Of course Gandalf must reappear later - probably fall is not as deep as it seemed. Gandalf thrusts Balrog underneath him & so ....& eventually the subterranean stream in the gulf he found a way out - but he does not turn up until they have had many adventures: not indeed until they are on borders of Mordor & the king of Ond is being beaten in battle.)

CT comments: This seems to show clearly that before ever the story of the fall of Gandalf from the Bridge of Khazad-dum was written, my father fully intended that he should return.)

Of course, this would have been too close to Gandalf's reappearance in TH just before the Battle of Five Armies, so on....

The intention always seems to have been that Gandalf would be around to play a major part in the Fall of Sauron. He just had to figure out how to separate him from the Company & probably to enhance his power.