From everything I've read, and what I poked around in last night, the new zones are geared for levels 45+. The starting zone's (Corathus Creep) mobs were all green and very light blue at level 70, the next zone over (The Undershore) were mostly dark blue with the occasional white and yellow.
I had a guild group go into The Hive and get owned. Their tank was about 14k buffed. So it's safe to say that, along with Dreadspire Keep, are two of the three 68-70 only zones.
The zones are really pretty though, I dig the graphics and the new character models for the mobs. They have illithids, werewolves, mushroom men, and new orc models; just a smorgasborge of eye candy.
All in all everything looks really promising with this, and judging from what I read about the high end content, I don't think the uber guilds on the servers will get through this expansion any time soon.
Edited, Wed Sep 14 18:07:56 2005 by Xaltinye