Coudn't fit it into comment, so here goes a thread.

As it was noted before - Woodie is awesome, though quite overpowered.

From my experience the problem is the following:
1. Woodie is absolutely autonomous in the beaver form if there is food (wood) around.
2. Woodie can stay in beaver form forever, without any repercussions.

Possible solution:
Replace the single "Curse" scale with two - "Curse" and "Personality".

The "Curse" scale will define duration of the curse - just like before.
It can be extended by eating logs, and can be decreased by staying close to Lucy.
Also goes down by receiving damage and degrades over time.

The "Personality" scale is meant to limit the time the player can stay in the beaver form. It goes down from 100 to 0. As soon as personality hits zero, the beaver form consumes Woodie's personality and player dies, possibly leaving the hostile Werebeaver NPC behind (optional).
Personality degrades over time during the curse, but will be deducted additionally each time werebeaver kills someone or destroys non-wooden entity.

To address the mutiplayer griefing issue I'd add a new totem recipe to the survival tab, that would fend off beavers and possibly other shapeshifters from the area around it.

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The rate at which personality degrades from various causes is a subject for tweaking, but it can help to make woodie less destructive to the environment while keeping the core mechanic intact and leaving some space for offensive maneuvres.

Hope my 2 cents help.