>>19123107Normal space marine armour already gives enough defense, there are different marks of space marine armour, for example mkiii was heavier but gave better defence. Terminator armour is pretty rare and aren't deployed in every battle, it's also bigger so terminator armoured guys are harder to transport, they are slower ofc than normal marines
So yeah, power armour is enough, terminator armour is used in special occasions
Scouts wear even lighter variant of power armour but i guess they don't need much defence