Be warned I don't know how to use the editor properly. Details for DAI that I found on Gamebanshee (which was take from a translation of German printed games magazine Gamestar). These are the basics:

Two new companions
-The bald elf mage called Solas who is an apostate and expert for the fade
-The Qunari Iron Bull. David Gaider describes with this words: He fears nothing only the past. 
-GameStar saw also an archer (likely Sera)
-The Inquisitor can make his/her own rifts in the fade and summon demons.It's not understood if this is a special ability for all Inquisitor classes or just the mage  class(personally I think we are finally getting a demon summoning blood mage) 
-No fade puzzles (transformations) like Origins
-Two voice actors for each gender. 
-Skyhold or Homebase system. You will also be able to customize certain rooms and buy upgrades, like a garden to grow plants for alchemy. The journalist also suspects that there will be a "map room", where you can allocate troops to open new trade routes or occupy outposts.
-dynamic wildlife. If you kill all the wolves in a forest they are gone for a while. In the same forest another player can met deer.
-new enemy giants they liken to Darkspawn ogres that can throw rocks.
-A dragon is especially vulnerable on the head

The rest you can read by following the link on Gamebanshee [1].