What exactly are the proc rates, ICD (if any), and hidden rules of the MoP weapon enchants?
Ask, and ye shall receive:
River's Song: 2PPM on melee attacks that land, or are dodged, or parried.
Dancing Steel: 1PPM on melee attacks that land.
Colossus: 3PPM on melee attacks that land, or are dodged, or parried, with a 3-second cooldown.
Elemental Force: 5PPM on melee damage, or non-periodic spell damage/healing, with a 0.1-second cooldown.
Jade Spirit: 10% chance on spell damage or healing, 50-second cooldown.
Windsong: 1PPM on melee damage, or non-periodic spell damage/healing, with a 1-second cooldown.