Until I did the Wisdom of the Druids quest (VERY out of the way), I had no clue what happened to the Druids. Furthermore I found them very unwilling to divulge any further information about themselves when I met them.
Could one of the next expansions perhaps call on them? I think they are very interesting.
Druids
Ristaron
BigTru
Err... Read the manual, do the Maguuma Jungle Bonuses, and read the insciptions at any manuement to Malandru. You will get all the info you need about Druid's there.