Exactly, Halo is not Halo without her. Halo is about two companions (The chief and Cortana) fighting together. You take that away you have not halo but another game. Halo is a game where you fight through the conflict together. I don't want some stupid clone of her, I want her with her memories in tact.
In that blog I posted their are seriously good ways for Cortana to come back to.
I don't know whether people just like the multiplayer and don't bother with the story, but I played my first Halo when it came out and I have seen the chief develop a relationship with Cortana and Cortana with the Chief. You stop that you basically stop the game in general.
I don't know about the majority but I love my story in the Halo games and I love the characters. Even if it is a computer game, Halo is not basically a computer game it's like a lifestyle you are attached to.
I have to say their is a lot of death in Halo, cap keys, Miranda Keyes, sgt Johnson etc etc, but I don't want Cortana to suffer the same fate, she is basically the best character in the game, not to mention the main character that puts Halo into Halo.