So, Todd Howard talked for a good 35 minutes at DICE, and he very briefly touched on the new Survival Mode they're working on. https://youtu.be/DKw2JpLAHdw?t=2h50m46s, set to around where he starts talking about it - Todd Howard starts at 2h30m, if you're curious to listen to the full thing. He talks about it not being harder "in the way you'd expect"... he also says it's some of the most fun he's had playing the game, and that it's totally different, but try to figure out how much of that is Howard the hype-man and how much is Howard the hardcoe gamer.
He talks about if you don't sleep, you'll get fatigued, and he even talks about getting insomnia. So it won't just be diseases contracted from wild critters like in Elder Scrolls. I know there's not many new details here to discuss, but I figured it's still worth mention. Do you think Survival Mode really will make the game feel completely different, or will it just be more like hardcoe mode in New Vegas?