The new Chinese Liu rifle infantrymen squad has 7 infantrymen, 1 engineer and 1 AT gunner while every other premium/event riflemen squads have 9 infantrymen.
I propose that players, if they want to, should be able to change 3 infantrymen to specialists like engineer, AT gunner, radio operator and others if possible just like tech tree infantrymen squads.
I know it is impossible to swap soldiers in premium and event squads so instead the squad upgrade should change the soldier´s class while his perks, perk points and everything it entails would stay the same for obvious reasons.