I made an account here because this conversation was rather appealing to me, and I thought I'd give my two cents no matter how odd it may be. I especially was intreagued by TheTallSpartan's post from 17 November 2012 - 12:17 PM, and his idea of human's being sucked into a "digital world" as well as the comments mentioning Cortana was created by Dr. Halsey's personality. If you implement those facts with the statement mentioned by Dr. Halsey herself in Spartan Ops episode 6 when she said,
"Life is too short. I will never learn all that exists in our tiny galaxy, let alone the rest of the universe... and I so despretely want to know everything."
I have a theory that Halsey could possibly be searching for eternal life for the purpose of intellectual persuit (ie. AI incarnation). Not only this, but Halsey demonstrates a unique care for John than anyone else, a care almost akin to Cortana's. Proof of this care can be found throughout the books, games, as well as in episode 7 when she learns of John's existence. All this, coupled with Halsey's knack for getting in the middle of important events makes her, in my opinion, a prime candidate for Master Chief's plus one.
Now take note that I do understand that AI's have an 8 year life span and that this is the whole reason we're having the conversation in the first place. But this is Halo, anything can happen. And for the record, I'm also in the boat that wishes that 343 would somehow bring back Cortana in a classy way, I just think that this might be a plausible idea as well.
Thank you for your time.
