Alright, now everyone just runs maximum explosive resistance under their shields. Try getting through this (
https://s.orbis.zone/cpkv) build with 47500 shields and 18000 effective hull for explosives. How much damage do you want the class 2 missiles do you want to deal to actually damage this? Do you want your missiles to deal more damage than a Huge multicannon?
Also, again, I can just run away from missiles in my cutter or courier. I don't need the ECM or PDC. I can just run with 6x regular shields and outrun or distance myself 2.5km away from the person with missiles and just dodge the missiles or by shooting at them with medium or small screening shell frags. It is safe to say even the new and improved missiles would be easily countered without sacrificing booster space.
Now, lets talk about how absolutely bad of a change this would be:
Small ships are forced to sacrifice a booster slot that it does not have for a ecm or pdc. Pretty much gives all other ships better shields.
Size two weapons are now being used as the entirety of the main armament: Literally all non railgun and MC weapons are now useless, since you can skip shields using the size two missiles at close range. PDCs and ECMS cannot counter a point blank dumbfire missile, and since you skip about 90% of their HP, shield tanks are useless.
No variety in gameplay. With only one weapon and only one counter (fast ships) Only hulltank ships would exist, killing variety.
Unrealistic. Missiles simply cannot go through shields. Even lasers cannot go through shields, and even the ones that do only phase through.