He is, but he is only in the explosion in the cut scene for the extended legendary portion. Which is what is being poked at here; that is not something that actually happened, just a humerous non-canon easter egg joke for people who survived legendary.
Being that he isnt there in the standard cut scene, he is to assumed to have left as is detailed in First Strike. (As is given support by the fact he is alive in the following novels and games, where as it is impossible to have survived the blast.)
In the interests of the thread however, I would say I am looking more forwards to Halo Wars. If not for the blind Bungieness, at least from my distaste of voice controls. Story wise, I have never been a 'huge' fan of Tom Clancy stories. They are nice, and are usually well thought out and connected, but they are too grounded in modern day politics and reality for me to find them entertaining.
Likey my games to break from the world around me, as opposed to "alternate universe" tales of the world I live in. Not to say thats bad, its just not my taste.