In a somewhat random post on the official TERA boards today, Senior Producer Brian Knox confirmed that the NA version of TERA will be launching at the level cap of 60, which was previously 58 in the Korean version. Additionally, current level 58 endgame dungeons will move up and down to spread the endgame content around for the late levels.
Knoxxer: Our max level will be 60 so all those 58 max level dungeons would have been a waste. We have shuffled them around -- some up and some down.
We will have more detailed information on it closer to open beta but it should create a much smoother progression to 60 as well as a good amount of content at level 60.
Read more from the thread over on the official site.