I think that Linda and all of the other surviving Spartans at the end of Glasslands will appear in Halo 4. I personally would love to see them in there, but later on in the game and not at the very beginning.
I personally don't mind, but I can see how some people wouldn't like it. So, if they did tag it with spoiler that would at least warn some people who don't want any spoilers.
Welcome to the Forum, Andrew. I am sure that you will enjoy all the other members, and the latest news that our News Group gathers. I hope to see you around soon.