Martin talks about how impressed he was that
The Avengers introduced Wonder Man, brought him into the group and killed him off, all in the same issue. And then comes this great bit, in which Martin confesses he thinks Wonder Man and Gandalf should both have stayed dead:
I do think that if you're bringing a character back, that a character has gone through death, that's a transformative experience. Even back in those days of Wonder Man and all that, I loved the fact that he died, and although I liked the character in later years, I wasn't so thrilled when he came back because that sort of undid the power of it. Much as I admire Tolkien, I once again always felt like Gandalf should have stayed dead. That was such an incredible sequence in Fellowship of the Ring when he faces the Balrog on the Khazad-dûm and he falls into the gulf, and his last words are, "Fly, you fools."
What power that had, how that grabbed me. And then he comes back as Gandalf the White, and if anything he's sort of improved. I never liked Gandalf the White as much as Gandalf the Grey, and I never liked him coming back. I think it would have been an even stronger story if Tolkien had left him dead.
My characters who come back from death are worse for wear. In some ways, they're not even the same characters anymore. The body may be moving, but some aspect of the spirit is changed or transformed, and they've lost something. One of the characters who has come back repeatedly from death is Beric Dondarrion, The Lightning Lord. Each time he's revived he loses a little more of himself. He was sent on a mission before his first death. He was sent on a mission to do something, and it's like, that's what he's clinging to. He's forgetting other things, he's forgetting who he is, or where he lived. He's forgotten the woman who he was once supposed to marry. Bits of his humanity are lost every time he comes back from death; he remembers that mission. His flesh is falling away from him, but this one thing, this purpose that he had is part of what's animating him and bringing him back to death. I think you see echoes of that with some of the other characters who have come back from death.