I also remember them stating that you may not even come across that particular plot line in your game. Almost made it sound like it was the beginnings of a 'failed' playthrough.
Yep
http://www.ausgamers...es/read/3456301
So it’s really very complex, about how much control the players have over the types of content. And as I was saying before, that whole demo you saw, in the last half of it, when you’re fighting with Alexius and Felix, not all the players are going to see that, because going into that area is the result of a branching choice in the game. So you may have picked another area and you wouldn’t be going into that castle at all, you’d be going somewhere else entirely.
There’s whole sections of the game that are like that, that we branch off entirely. You can go to Red Cliff Village, and see the consequences of you picking the other decision. So we’ve made sure that any exclusive content, you can still see the flip side of the consequences as well.
Also this from this interview at E3 Cameron Lee mentions how the mage/templar conflict choice leads to exclusive content and how "part of what you saw in the demo today is a little section of that choice"
~2min in https://www.youtube....h?v=5MSIW7JR5yA
Also keep in mind that they've also said that we are lacking context to what's going on and they said they had to cut a bunch of dialogues and content that was too spoilery