Still have the game pre-ordered but I watched that GameSpot video yesterday and to be perfectly honest, that turned me off more than on to the game. The main reason was the "perks" system replacing all of the crafting and skill tree from previous games and being tied to completing "challenges". The entire hunting, skinning of animals and crafting that's tied to this is all gone. Now, the animal skins are basically just loot since all you do with it is sell it. This change completely defeats the point and purpose of having animals in the game now. No reason for me to hunt animals unless it's required to complete a main/side quest. Simply disappointed with the decision to change this aspect.
As for the DLC, im expecting each one to be an average of 3 hours each, maybe less. The trailer for it says, get it, complete your objective and get out. That tells me that they will be short quick experiences. At least, that's how it sounds in the DLC trailer.