Sorry, don't have the rulebook in front of me but
Striking as wind was changed to allow you to spend opportunity to reserve one dice per opportunity and use their result in place of an equal number/type of dice next turn.
It is unclear if the reserved dice can also be used during the initial roll. My instinct is that you can't keep and reserve the same die given the flavor text of setting up for a future opportunity, but if that is the case, then this ability seems extremely weak as you'd be trading an opportunity and a future dice (so -2 dice) to delay a current dice until next turn (when the fast combat promotes immediate effects)
If you can use the dice you reserve it's at least usable as you can repeat exploding/success+opportunity to trade one opportunity and a dice next turn for a dice worth on average two in its place. Seems a bit situational with short combat limiting abilities that do nothing the turn you use them, but in longer combat it can set up a few crits or points of damage which is nice.
Edited by Moderately