Initial reactions:
This reminds me of a variant initiative system from Len Lakofka's Leomund's Tiny Hut column in The Dragon, that was very popular in my area (I used something like it for a decade), but not so much of AD&D's actual initiative system (aside from being complicated and inconsistent, that is).
Maybe I'm not remembering the official one in enough detail?
Initiative Dice
Die Action
d4 Ranged attack
d6 Movement
Swap gear
Any other action
d8 Melee attack
Still seems you can draw, knock, pull, and loose an arrow before an adjacent enemy can hit you in the face, fairly consistently. Maybe if you're Legolas.
It's bad enough ranged attacks don't draw AoOs (among other things).
Weird.
Multiple Actions. If an effect grants you an
additional action without the use of a bonus
action, you roll an initiative die for only one of
your actions. Use the largest die that
corresponds to any one of the actions you plan to
take.
If the system addresses extra attacks anywhere else, I missed it. Apparently attacking two or more times is somehow /not/ attacking any faster. At least it's not attacking /slower/, like bonus actions apparently are.
What about Extra Attack, or at least Action Surge, reducing your initiative for the first attack/action?
For instance, when you Action Surge you roll your initiative, take one action at 1/2 the result, and the second normally.
Delaying. You cannot use the Ready action
under these rules, but you can instead choose to
delay your turn. Instead of taking your turn on
your initiative count, you simply act on a later
initiative count, before or after other creatures
as you choose. I
That's generous.
I'd think if you're genuinely dithering, you shouldn't roll initiative until you decide what you do, then, on the count you make that decision, roll initiative and add it to the current count.
I think Ready could work, too. When rolling initiative, state the specific action you're readying. If you beat the initiative of the creature who triggers the ready, you can use your Reaction to interrupt it or just take your action right after it finishes (but still have your Reaction). If it beats you, you don't get to take the readied action.
Edit: I feel like there needs to be a 'too slow' rule, like if you do too much and roll too high there's a threshold where your action rolls over into the next round.
Variant: Spell Disruption
For added AD&D flavor, you can introduce the spell
disruption rule. Under this rule, if a creature that wants
to cast a spell takes damage during the round before it
can act, it is restricted to casting cantrips on its turn.
Wow, that is weak. And double-dog-optional-variant-optional. I guess putting casters at any kind of disadvantage is all but unthinkable.
For Added D&D flavor, maybe add the level of the slot to the die roll, and if you're hit 'between' the die roll and the level modifier, the spell is spoiled and the slot lost. (At least, I think that's pretty close to one of the two conflicting AD&D casting-in-melee rules...)
