I'll just add to what Spoekes and Fahna / VanEinstein spoke above

Fey Wind = 100% chance to get a 3% haste buff for 30 seconds every minute = effective average of 1.500% haste every minute
AST = 10.2%* chance to get a 5% haste buff for 15 seconds every minute = effective average of 0.128% haste every minute

* Assuming the AST is aiming for Expand Arrow every minute to match Fey Wind, you have a 33.3% (1/6) chance of getting the right Royal Road and a 30.6% chance of getting Arrow w/ Shuffle up (1 - 5/6*5/6 OR 1/6 + 5/6*1/6)

And even on perfect probability

Fey Wind = 3% haste buff for 30 seconds every minute = average of 1.50% haste every minute
AST = 5% haste buff for 15 seconds every minute = average of 1.25% haste every minute

The more I look at it, the more I feel Arrow should almost never be Expanded and just used on a single target who can make the best use of it (NIN, MNK, OT WAR, any DPS about to begin their burst)