Spoilers below...
Now that the artifact is a major point of the story (which I think is a great change), I think Larian have missed a trick with the Minthara conversation.
Minthara says she's looking for the grove because she's looking for the artifact. Its lucky that she first asks "Where is the grove?" and not "Do we have the artifact?"
My suggestion is that the narrator should explain that Minthara probes deeper into our mind and is getting closer to finding out that we have the artifact.
The dialogue can then suggest that we distract Minthara by giving her the location of the grove before she can delve deeper into our minds to discover that we have the artifact. Our playing along with her is a diversionary tactic to keep her from finding out that we have it.
This would make the option of helping the goblins destroy the grove simply a side effect of distracting Minthara and not the main point of the evil route as it feels currently.
