Entrenchment, Diplomacy, Rebellion

Any weapon can be modded to ignore shields, it's not just a property exclusive to phase missiles.  7 Deadly Sins has toyed around with this giving a variety of weapons "Phasic" properties -to bypass shields to some extent. Adding this line to any research subject and applying the appropriate

researchModifier
    modifierType "WeaponIgnoresShieldsAdjustment"
    baseValue 0.000000 [1.000000 is 100% shield bypass, 0.100000 is 10%, 0.350000 is 35% and so on.]
    perLevelValue 0.000000 [0.050000 is 5% per level, 0.100000 is 10%, and so on]
    linkedWeaponClass "" [insert appropriate weapon class]

Be sure to change the MaxNumResearchLevels and the researchFloatModifiers # to match the number of researchModifiers to avoid issues.

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I think Diplomacy, but definitely Rebellion.  Impenetrable to 'partially' impenetrable shields.

To defeat phasic weapons that bypass shields to x%.  Vasari can get 30% max shield ignore, but mods can buff that to more and screw around with all sorts of weapon class so anything can bypass shields -the trick is being able to bs well enough in the English.str file descriptions.

Just playing around with RESEARCHSUBJECT_SHIELDSTECH1.entity, I did this:

onlyWorksIfTierLabsExist FALSE [if TRUE, you don't need labs for it to work, also means baseValue apply at game start]
MaxNumResearchLevels 4 [was 2 levels, but I wanted to test 25% phasic blocking increments]
priority 1.000000
researchBoolModifiers 0
researchFloatModifiers 3 [there are 3 researchModifiers so gotta do the numbering right]
researchModifier
    modifierType "ShieldPointsMaxAdjustment"
    baseValue 0.000000
    perLevelValue 0.050000
researchModifier
    modifierType "ShieldPointsRegenAdjustment"
    baseValue 0.000000
    perLevelValue 0.050000
researchModifier
    modifierType "ChanceToIgnoreShieldsAsDamageTarget"
    baseValue 0.000000 [-1.000000 would be 100% blocking, but... that's for after]
    perLevelValue -0.250000 [25% phase blocking per 4 MaxNumResearchLevels]

When fully researched, phasic weapons don't get past your shields, but they will pound your shields down like normal weapons and chew into hull.
*if the baseValue for the "CTISADT" is set, for example, to 0.500000, then weapons will pass 50% damage to shields and 50% to hull.  If 1.000000, then all damage go straight to hull and you will die with shields up. 
**if the baseValue for the "CTISADT" is set to 0.3 and the "onlyworksiftierlabsexist" is TRUE, then once you get the labs, you get the base 30% phasic value.  If "onlyworksiftierlabsexist" is FALSE, you get the bonus when game starts -neat.
***perLevelValue, this determines how much boost per level.  0.010000 is 1%, 0.100000 is 10% and 1.000000 is 100%.  If you put in 5.000000 for perLevelValue, 500% might not mean 5x more damage, but who knows. 

    baseValue -0.100000
    perLevelValue -0.050000

This means, depending on "onlyWorksIfTierLabsExist" TRUE/FALSE, you block 10% of phasic damage and with research gain an additional 5% phasic blocking per level.

If you want to make the Vasari even more unbalanced, give them this.  If you want to give TEC and Advent some reverse engineering of phase missiles to they don't get ripped by them, give them this.

We're doing this for the Empire in 7 Deadly Sins to fit canonically weak armor and strong shields and fluff material for them and realized other mods could benefit from this. 

Enjoy phasic weapons and blocking them.