A UI idea for consideration:
- When it's not your turn, have a "reactions wheel" appear on screen, greyed out.
- It has one large button "Pass" that your mouse cursor automatically moves to at the end of your turn.
- If anything happens that could trigger a reaction from any of your characters, the combat goes slow-mo and the cause is clearly indicated.
- Around the "Pass" button appears buttons indicating what reaction abilities are available (little head icons per party member) that matches the trigger. If you want to use one of them, click their button.
- If you want to hold your reaction and pass on this event, hit the Pass button.
- If there's no triggers, then there's no buttons. No problem!