Explorer areas really need some love in ddo, as they don't currently offer an incentive to do them aside from the initial XP gain of grabbing all the explorer areas/notes.
Several changes are needed:
1. HUGE increase in XP from kills, reduced amount of kills in top tiers
2. Add named loot to chests in explorers that currently don't drop tome pages, commendations etc.
3. Add some "boss named" that require a group to kill
I was driven to this when I spent 4 hours yesterday exploring the entire under dark (not schinndlryn), and was just saddened that up until yesterday i had never set foot there as there is simply no point in ever going there. While many areas seemed bland and stale and overly large, I did enjoy being in the frightening under dark, and just wish there was more of a reason to stay there.