SOE's David Georgeson walked Gamescom attendees through some of the finer points of both EverQuest Next and EverQuest Next: Landmark today, focusing on the emergent gameplay, destructible environments, and vast flexibility you'll potentially find in both halves of the game.
Most of the information provided on EverQuest Next falls into the "things we already knew" category: The world is procedurally generated, destructible, tiered, and made of voxels. AI responds to your actions in lieu of sticking to specific spawn points; for example, Orcs will naturally search for areas with low guard patrols and high traffic so they can make the most of their thievery and will leave for greener pastures should you start making their work difficult by killing them or alerting guards.
There were new details on Landmark, however (check out this great post from MJ to see what we knew before). You can choose between male and female heroes and will begin as an Adventurer class at one of the world's great landmarks. From there, you can adventure freely into the world, find a spot you like, and claim it as your own. Once your spot is claimed, you can build on it however you see fit or move on to claim other areas and link them all together.