What you are now describing is a gamedesign that doesnt work properly. Thats what they did here, they have made a mechanic that doesnt make sense,first of all, and is very hard to balance.
If the Reinforcement soldiers are replaced by lets say…a Recruit wearing a Assault rifle(ironsights,decent damage), 1 syringe for themselves, they ar emore than capable to survive till the end.
I dont want them to come back with the same loadout and perks, giving me a snipershot or a nadelauncher when i BARELY killed them off the first time,becasue they were good or has OP weapons that melts the Pred.
ITs not fun man, and as it stands now, a Pred cannot stop a reinforcement form happening, thats VERY rare.