Skill is terrible and it should feel terrible.
It goes in the exact opposite direction that MNK was built in. It effectively cancels out Grease Lightning while also working against the Deep Mediation passive by allowing less GCDs being used during its duration and since TFC has become MNK's unfortunate crutch to hold us up as DPS, using RoF is a slap to the face as a skill.

Brotherhood or not, RoF is a god awful skill that needs a complete rework IMO. I'd settle for just a 15% damage buff without the drawback of killing our chef mechanics.