I played a D&D 3.5 campaign years ago, and one PC was a druid. The player did a pretty awesome job as a spy thanks to the multiple divination spells, Wild Shape and especially A Thousand Faces:
A Thousand Faces (Su)
At 13th level, a druid gains the ability to change her appearance at will, as if using the disguise self spell, but only while in her normal form. This affects the druid’s body but not her possessions. It is not an illusory effect, but a minor physical alteration of the druid’s appearance, within the limits described for the spell.
I'm now planning to run a Pathfinder campaign (albeit with a custom world) with a lot of druids and I just don't understand how Thousand Faces fits for a "protector of the wild, lover of Nature" kind of guy (and I've never seen this ability used since this spy-druid), so I'm considering dropping A Thousand Faces.
Did you ever read something justifying this ability, in D&D or Pathfinder material or anywhere else, even real stories on druids?
EDIT : What bugs me is that I can't see proper use of this ability besides deception, and deception doesn't feel too "natural".