^^^ I saw that as well. Aside from the graphics and detail, the third person stuff is what caught my eye. I never heard of the game or series until this year, but they should look at this as a series progression and gameplay enhancement.
But what's the deal on the DLC and the different versions?
So you've never played the first two? The first is amazing and the second isn't too bad but it was such a disappointment they actually fired the entire development team. As far as the series progression and storyline if anything they aren't adding anything new since everything you see in this game was already in the first, so it will rely completely on the gameplay..
As far as download content you can read on here:
WHAT ABOUT MULTIPLE ENDINGS & REPLAYABILITY?
Several endings are confirmed for Deus Ex: Human Revolution - each the climax of a substantial campaign. You won't be able to experience all the augmentations or weapons on the first play through - economy will come into play. Just like in real life - you can't have it all. You can play again and have new abilities, new weapons and these will affect your game experience, opening new areas. You can't have everything at once; some decisions will mean the forfeit of alternatives.
http://forums.eidosgames.com/showthread.php?t=86841
Basically the EX Mode will be the best we have ever seen. So I wouldn't see any reason for DLC, but its hard to say if they will release anything in the future..