I think most players enjoy the battle royale as it can pose a lot of unique fights people don't get to engage in otherwise. However, PK for the sake of PK alone isn't always enough to draw people in.

I think quests might be fun as they related to an area, maybe one of the lesser visited ones. So for example, Sulwine leads a siege against Fahlugash. A second Imm leading the orc side, might be fun, though probably more complex. Or a battle in Mortorn between Ludan and Grazzaar or something. Where people get to sort of participate in a battle related to the lore of an area. There are lots of interesting stories in Thera, giving PCs a chance to engage themselves into them might be fun. Even an escort quest might be fun.

I also think any quest event that leads to any lasting mark on Thera is sure to get people involved. Even if it is something as small as a name etched into a cave wall or something. Maybe I'm wrong, but achieving any sort of permanent mark on Thera is a chance most characters would jump at.