I haven't yet convinced my group to use something like this, but I used it a lot in AD&D. It work really well in theater of the mind, but much less so with miniatures. The free form narrative style of TotM allows some inconsistencies to be smoothed over.
Works
- Declaring actions in advance. Speeds up gameplay as all players (and the DM's monsters) are figuring out what they are doing simultaneously rather than one-at-a-time. Consider allowing players option to always "cancel" any declared action in favor of Dash, Dodge, Disengage, and consider allowing anyone to sub in a very similar action (e.g. I was going to attack with my axe, but the enemy is now next to a wall of fire and I want to Shove them in (a special attack), perhaps using the axe).
The easiest method is to keep the actions simple. You state if you plan a melee attack, ranged attack, spell, etc. Movement isn't declared unless it's extremely important, such as blocking enemies from getting to a spot (intercepting enemies going for the back line characters, blocking off retreat, etc).
Doesn't Work
- Declaring bonus actions (way too much bookkeeping) and movement. Those are generally dependent on the primary action, and given the limited # of bonus actions, don't contribute heavily to "analysis paralysis."
Yeah, bonus actions and movement really need to be free flowing, including non-actions like item interactions. I'd have everything but movement work similar to reactions, where you choose if you want to use them when they'd be appropriate. Movement would work as needed to complete the action, or bonus action if unused.
Curious
- Simultaneous actions. Haven't tried this. Applied it in AD&D days for nearly a decade. Currently use a "highest DEX score wins, otherwise rolloff with d20" for ties. It makes sense though. I just don't know how to apply it in a day when there's bonus actions and reactions.
Rather than just focusing on dex, I'd consider using contested checks appropriate to the actions. Unless the actions would specifically counter each other (i.e. only one person can succeed), why not just let everything occur, then resolve the effects afterward? For example, everyone rolls their attacks and casts their spells, but those who'd die or become disabled still resolve their actions. Conditions don't happen until after resolution, then last at least until the end of the following round's resolution (based on normal duration).