I've been using the DMG speed factor variant and looked over the Greyhawk variant, so some of this is familiar. And, in actual gameplay as I've documented in another thread, "losing" an action is a very rare event.
I do hope so. I don't intend the rule to be penalizing, just to encourage better cooperation.
Movement: The +1d6 modifier should be clarified for the option to move in case it'd be counterproductive when your turn comes up. You're still penalized for not setting your feet, Greyhawk style.
The 1d6 applies if you declare that you're going to move. You aren't required to move if you declare it, but you can't move if you don't declare it. So the 1d6 really does apply to the option to move.
Weapons: Hey, the d12 gets some love. In your monster section, what about a Giant with a giant-sized knife? Do you have a size modifier built in to account for this?
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Size. As above, does it make sense to penalize larger weapons but not larger creatures?
I don't have any modifiers for creature size. I do see the value of having one, but I also want to keep the modifiers to a minimum (especially since I've been using dice as modifiers). I'll see how things play out. If I decide I need a modifier, my go-to fix will be a static modifier for size: -2 per size category above medium, and +2 per size category below medium.
Do ranged weapons act differently? What about loading weapons?
My variant treats ranged weapons the same as melee weapons (except that you're less likely to have to move when using a ranged weapon, so you're more likely to use 1d10 + modifier instead of 1d6 + modifier), and it ignores the loading property. Loading already comes with a steep enough penalty in the form of being able to make only a single attack.
Are you accounting (or caring) for the argument that Reach matters? A criticism of weapon speed is that fantasy armies of creatures with daggers and short swords should overwhelm armies with long swords, pikes, etc., due to superior initiative.
It makes sense to me to make reach weapons faster than non-reach weapons. However, I decided to ignore that for simplicity. If I decide through play that I need to account for it, I'll treat the reach quality as granting a +2 initiative bonus.
Special Actions: Does this include all class abilities such as clerical Channel? What about class abilities that mimic spells? What about if a class ability is a "bonus" action?
It includes all abilities used in your action that aren't covered by other entries. If an ability mimics a spell, I don't treat it as a spell unless you cast it like a spell.
Spells: Casters seem to get hosed under this system. In the DMG variant, it's -1 per spell level so that a 2nd level spell is akin to a heavy weapon, and a 5th level spell is like loading a crossbow. I get the impression they'll generally always go last if they do anything but cast a Cantrip.
Casters don't really get "hosed," but they are more likely to act later. The +1d4 does help offset some of the spell level penalty for low-level spells (which was my intent). If we assume an average d4 die result of 2.5, the caster is left with a +1 modifier for a first level spell and a 0 modifier for a second level spell. It's only for spells above second level that the caster starts to (on average) have a negative modifier.
Other: Do Bonus actions and normal Actions stack modifiers? (Under DMG variant they do). If not, how do you account for them?
For the sake of simplicity, I'm opting not to account for bonus actions and to base the modifier entirely on what a player declares she'll do with her action. I don't really see the need to account for the bonus action, because I don't see the potential for brokenness; that is to say I don't see how a character will get a meaningful benefit from declaring a dagger attack with her action and doing something slower with her bonus action. Please note that I may be overlooking something, that's certainly possible.
Improvised actions, are these like opening a door, using a lever, etc.? What if one is vastly different, such as tying a knot versus simply pushing a door open? Or does the +1d6 already account for what can happen in 6 seconds? In the variant, the DM decides arbitrarily whether to assign a penalty modifier.
By Improvised Action I mean an action that requires me to decide how to mechanically resolve it. Opening a door or operating a lever are just object interactions. Maybe I should include a modifier for that, but I truly do want to keep this simple without just simplifying it down to a single and very swingy die roll.
By way of contrast, an improvised action is something more like attempting to drop a chandelier on a creature, using the circular part of the chandelier to hold the creature's limbs to its sides until it can wriggle or break free.
That's a lot of dice rolling. Assuming bonus actions stack, if I want to move, attack with my longsword, and cast Healing Word as a bonus action, I'm rolling 1d6+my modifier + 1d8 + 1d4 minus 1. That's, relative to the original system, a lot of rolls and math each round. Plus, if you have diverse enemies, you the DM are having to track the same thing. What if the party is facing another adventuring party? You, the DM, might be rolling and tracking 3 different dice each round for each enemy. Are you concerned about slowing combat down?
It's two dice: one base die (determined by whether you declare movement or not) + one modifier die.
I originally wanted to change the initiative roll to just 2d10 to reduce the swinginess. When coming up with the variant, I specifically wanted to keep the dice rolled down to just two.
So, in your example of moving, attacking with a longsword, and casting Healing Word, your initiative would be 1d6 + 1d8. With average results (3.5 & 4.5), that would be an 8.
