ravage is dependant to Feral strike , you have have to cast feral strike first before you can use ravage , at least that's how it works if you use Aegipan , dunno if the mechanicks from COTW allows it to work alone .
anyhow , ravage provides very fast attacks , allowing you to proc like crazy "on attack" . similar to what Massacre used to do , but with 10 hits each attack , ( 50% wd , boosting the attack rating and physical damage ).
i am curently updating one of my treewarden builds arround it