Quote Originally Posted by ICountFrom0 View Post
Overpower -> Mythril Tempest gives surging tempest

Is it better to use those to extend the buff by 30 seconds in 2 GCD, or is it better to continue to use Storm's Eye?
2x Heavy Swing (200p) + Maim (280p) + Storm's Eye (400p) = 400p + 560p + 800p = 1760 potency in six weaponskills.
3x Overpower (110p) + Mythril Tempest (150p) = 330p + 450p = 780 potency in six weaponskills, you gain +20 more Beast gauge, amounting to 66 potency roughly in average potency gain from Fell Cleaves replacing weaponskills.

For Single-Target damage the answer is very clear.