What does this accomplish that 1,000,000 other things don't accomplish better?
With CS Heracross you can guaranteed outspeed your opponent and kill him before he can even hit you, not only eliminating a need for Focus Sash but freeing up another moveslot where Swords Dance was.
CB/Life Orb Heracross makes Swords Dance a moot point, and with no stat-upping move Focus Sash is pointless anyway to try and get in the boost, because hey, you don't need to get it in because you already have it.
If you were trying to outspeed the opponent so that you could survive him hitting first, then Focus Sash would be understandable. But if he's faster than you, there's no point getting in the Swords Dance because he'll KO you next turn. If you want to be faster than him, go with CS, or Endure+Salac. Either way, Focus Sash is better left to other pokes.