I wouldn't say wind is completely useless though, I have not stepped into coil yet, but I know when I'm doing Titan-HM's I switch between all 3 flavors of fist.

1. Fire - I use this 99% of the time pre p5, and through all of heart of course.
2. Earth - I use this during tremor, help the healers out
3. Wind - I use this in P5, helps ensure I take absolutely no damage from anything avoidable. Gets me out of plumes faster, away from bombs quicker, and attacked the boss sooner helping to make sure I don't lose GL stacks.