I learned a few more tidbits about TERA from an interview posted at theGamerVg. One of the more unique concepts will be targeting/aiming. If I understand correctly, where you first aim is where the attack or spell will land, even if the mob or player moves. So groups will need to keep the mob steady so that all ranged attacks will actually land. And this will apply to healers as well. If the tank keeps running around, they will not be able to heal. There will be collision to prevent mobs from running through the tank. This sounds like it could really offer a fun challenge for groups and I'm curious to see this in action.
There was also definite confirmation on PvE/PvP. The PvP servers will be open world PvP, while the PvP on PvE servers will be strictly consensual either by dueling or entering their battleground system. But they have stated their focus will be on the PvE experience much more so than their Korean counterpart, and they are adding enough quests from 1-60 so there will never be any grind required. And while there is a strong focus on group play, they are adding additional skills and areas so that soloing is a viable option as well.
There was also vague mention of crafting where you'd be able to take regular gear and craft it up to be epic gear equivalent to what would drop from dungeon monsters. But given where the game was original developed, I'm not expecting an involved crafting system such as EQ2 or LotRO.
Their trailer can be found here.