Never thought I'd say this, but: use a dice pool. Nothing says "flurry of blows" like a flurry of dice. Each of your attacks is a d6, your results must exceed your opponent's damage threshold, and you can chain all of the 6's together for an ULTRA COMBO!
I'm pondering ways to do that which would be fun and visceral. I had a thought to try to capture how a player might balance their offense and defense while dealing with swarms of mooks.
One of my friends bought three bricks of d6s for FATE - 27 each in red, blue, and green - which had two sides with plus signs, two sides with minus signs, and two sides blank.
What if you had, I dunno, a starting dice pool of three (which could increase with level), and at the start of each turn you pull three dice of any color or combination of colors, which you have access to for the turn.
Red represents offense. You use them to make bonus attacks at any point during the turn - including as counterattacks when someone comes at you. Plus (+) means you hit and deal 2 dmg. Blank ( ) means you hit and deal 1 dmg. Minus (-) means you miss.
Blue represents defense. You use them to possibly negate attacks, either by dodging or parrying. Plus (+) let you negate an attack or end a condition. Blank ( ) reduces the damage you take by 1. Minus (-) means the attack hits as normal.
Green represents tricks. You use them to do stuff like throw, trip, blind, stun, and the like. Enemies would have some sort of threshold (usually just 1 for mooks, but maybe 3 or 4 for bosses). When you hit someone, you can roll a trick die. Plus (+) adds 2 step toward the threshold. Blank ( ) inflicts 1 step. Minus (-) does nothing. If you reach the target's threshold, you get to choose a condition you apply. . . . Or maybe the condition is preset based on what weapon you're attacking with?
This would be separate from supers (attacks would still use 2d10, and you could trigger a super by spending a Peril point or by rolling pairs on the dice). So on a typical turn you'd have 2d10 to attack with, and 3 other dice you could roll during the turn. It's still a bit random, but it's giving you some control over how much you want to commit to offense, defense, and conditions.
The number of dice would need to be playtested to figure out what's meaningful and fun without being too strong. Balancing 'feeling cool' versus 'feeling threatened' is hard. Which segues into the next thing I need to come up with: enemy design.