http://legion.wowhead.com/item=13703...=1811#comments
It states: Run Through deals increased damage equal to 50% of your increased movement speed.
So....
Baseline: Fleet Footed: 15% increased movement speed, permanent.
Baseline: Sprint: 70% increased movement speed for 8s, 1 min CD.
Talent [T30]: Hit & Run: 15% increased movement speed, permanent (effectively turning a utility tier into a DPS tier).
Class Synergy: Windwalking: 25% increased movement speed from Monk, permanent (need the +15% talent).
Class Synergy: Windrush Totem: 60% increased movement speed from Shaman, 15s duration; 2 min CD
Race Synergy: Darkflight: 40% increased movement speed from Worgen race, 2 min CD.
... lel?
So you can have a burst +% increase damage to Run through of... 112.5%.