Thanks for the feedback.

Berserk is meant to do two things. First, it helps to capture the hurricane in a bottle feel. The Protean Chimera doesn't have full control when she unleashes herself. She struggles to prevent the destructive force she represent fly out of control. Second, Chimera Form is a really powerful ability and Berserk forces the Chimera to shut it down early if she doesn't play her cards right.

If you're fighting one bit monster the Chimera is probably going to be going toe-to-toe with it. If she goes Berserk she's going to be going after whatever has been attacking her first, eg, the bad guy. Once that monster is dead if the Chimera hasn't managed to reign in Berserk yet she can simply end the ability as a Full-Round action.

If there are more foes then you end up playing a little mini-game with your party. You shuffle around to make sure the Chimera eats the little monsters instead of buddies. And if it looks like she's about to munch the Rogue on her next turn she can, again, end Chimera Form.

Most of the custom feats for the Protean Chimera are aimed at mitigating the downside to Chimera form. Some make it so the berserk pool fills up more slowly, some make it drain faster, some give more Chimera Form uses per day so you don't need to worry so much about canceling Chimera form, and the Aspect of the Beast feat chain is all about increasing the Chimera's power in her base form.

I made Int the stat that lowers the Berserk pool because it represents the Chimera's rational, logical mind (Int) trying to overcoming the instinctual part of her mind (Wis). And for a mechanical reason as well. If she needed to pump Wis then she would be shoehorned into a more Wis focused build. But with the Face-Stealer feat the Chimera also has the choice of running a more Ch-focused build. That and the Chimera has several skills that she is more or less required to rank up due to the function of her abilities, so the extra skill points from Int help.

I really don't think the Chimera needs more features at this point. She already boasts a pretty impressive degree of flexibility and utility both in and out of combat.

With the above points in mind regarding Berserk, do you still feel the Berserk pool needs to decay more quickly?