That's a really tough call.
343i made an incredible game with Halo 4. The graphics, gameplay, music (though I do really miss O'Donnell & Salvatori!), and story were all great. Cortana's death, does, however, introduce a totally new element to the series.
Throughout all 3 first Halo games, Master Chief is able to pull off whatever he wants. In Halo 2, when he sends the bomb to the Covenant crusier, Cortana is worried he'll miss. He assures her, "I won't," and he doesn't. In Halo 3, he indeed does not make a promise that he cannot keep. Goodness, much of Halo 3 is about rescuing Cortana! Chief does what everyone thinks can't be done. Who doesn't feel a swell of nostalgic emotion when the rescued Cortana says, "Keep your head down; there's two of us in here now" in Halo 3? And Johnson's last words are, "Don't you ever, ever leave her" (I did miss the Johnson character in Halo 3! There's no one who quite replaces him).
So you spend all of Halo 4 trying to get back to earth, to do the impossible (again) and save Cortana, and keep another promise to her... and Chief fails (to save Cortana, at least). Johnson's last wish... (kind of) not met. All Chief's efforts in Halo 3... apparently for naught. It's a real bummer, and a real direction change. If she had to die, at least she died saving humanity (or, as she hinted in her "I'm not doing it for them" line, more specifically, saving John-117).
The new trilogy, then, may be different. Johnson's tough-as-nails character is replaced by the younger, softer, but still cool Latsky. Chief is a legend, but a bit archaic compared to the Spartan-IVs now. And he is, for the first time ever, without Cortana and unable to pull off the impossible. Am I reading too much philosophy into what 343 is doing? Is this a message for us aging Halo players as the youth of black-and-white idealism is replaced by the middle age of grayed practicality?
Now that Cortana is dead, I say leave her dead. Comebacks aren't my thing. However, I suspect 343 will somehow bring her back. She was a fun character; her humor was a great tag-along on the campaign adventures, and she'll be missed. The direction of the new trilogy, however, seems to be focused on John-117's humanity ("Which one of is not the machine?"), so we'll see what they do with that.
Thanks for letting me write a little existential essay. 343, if you're reading this, special thanks to you for your interest in your fans' thoughts.
