Wondering if anyone has considered applying the Simultaneous Movement rules from Chainmail?
Whether players take turns finalizing their character actions after the GM writes them out for the opponents first, or everyone writes the actions out for everyone they control simultaneously, one second passes in game time when its all resolved.
If a character's action wouldn't make sense anymore (if their target dies or isn't standing still anymore) they could roll a save throw with a relevant stat/skill to prevent a fumble: spells will fizzle or trigger chaos magic. arrows hit unintended targets, melee attack swings wide with lost balance, misc. Actually, did grognards playing Chainmail do something like that already? What did you do instead if not that?
There could be an advantage like "Quick Thinking" that allows you to change targets or withhold action; preventing the need to roll a save but with some sort of other cost.
Edit: Dude who's video I linked to apparently hates RPGPundit, given how fast he deleted my comment linking this message.
Or he hates me, whatever. No need to share his channel then.
huh, that could work. You'd have to try it. Maybe print out cards with the actual maneuvers on them. My players don't usually know the rules that well.