Initiative dice and d12 dramas

So recently ive been rewriting my initiative system and had a look over my various games for how to do it to compare and my FB readers gave some input. 

So im probably doing a checklist to see who detects the other side first is most likely to control what happens next.

Round zero is for ambush attacks, guards with ready-loaded weapons and some other circumstances.

I break round into magic both sides
Then missiles
Then melee
usually, you move then spell or missile or missile

i prefer group initiative but some exceptions can happen
if the battlefield is shaken up possibly reroll group initiatives

In closing melee longer weapons help in the closing round
a few skills capitalise on exceptions to all this
I will use dice and some mods to resolve ties but draws are possible.

I do like the Steve Perrin method of count down DEX scores and half for second att etc

d6 is good for simplicity +bonus will make more likely for players to win
d10 I used for years and im just asking why now + bonus
d20 is promising that its just a DEX roll

some dice and suns systems i appreciate were different just to highlight a different modular micro game and to stand out as a different sort of procedure. BRP RPG doesnt use d12. Some games assigned dice for stuff because dice were sold in sets so they felt obligated to using them.

D20 fits with other dice I use like stat/skill/save/attack and has come to be a sort of go to universal mechanic. Ive really been tempted to make all of them roll low under stats with less plusses. I liked Iron Crown system had a combat manoeuvre roll to let you move on battlefields and get advantages which is interesting.

The Winner
So after d100 I like d12 its no secret. 

Group Initiative - some individuals might be faster or slower than group norm
Only use initiative roll when there is a possible tie or ambiguity
- if one side A has no missiles or spells and side B does, side B will act first

Superior senses, alertness, range of senses, noise, nightvision may decide who is first
Those who detect the other side first can choose to:
-attack, prepare an ambush, cast spells, hide, parley, repeat until exposed
With surprise and other conditions, one side gains a round zero action
The winning side usually keeps initiative unless:
- battlefield chaos like fog, changing terrain, crowded, fog, and illusions might initiate a new roll
-parley might reset the initiate checklist and require a roll to resolve once close and talking
 
Spell Casting phase - casters cast spells first (any magic powers, songs, shapechanging)
Missile shooting phase - shots from missile attacks (any ranged attack)
Melee attack phase - strikes from melee attacks (any attack or other physical action)

If one side has melee and the other side has spells and missiles they will go first, only use initiative score when sides more or less equal position  

4d12 Encounder dice rolls
d12 for Local common encounters 
d12 for morale tests BX style  + Cha of boss bonus
d12 for reactions (most versions use 2d6) + Cha bonus + bard fx
d12 for initiative fits into these factors well + DEx and some class and skill mods

i can colour code 4x d12 and roll at once and perhaps place them on a table as a tracker
the players will mostly roll one d12 for the initiative but if they have followers they might want morale also

red d12 - 6 - encounter - orc hunters
yellow d12 -3 - morale - feeling brave and feisty
blue d12 - 11 - reactions - friendly
green d12 - 5 initiative as of round 1 if it comes up vs players 3

I kinda like putting these things together to see how the monsters react
these orcs are confident and assume the players are here with permission 

red d12 - 8 - encounter - orc soldiers
yellow d12 -1 - morale - fanatically bold and assured
blue d12 - 2 - reactions - angry will attack
green d12 - 9 initiative as of round 1 if it comes up vs players 2

these guys are more confident and unfriendly