You raised another point I hadn't thought of. What about the uniqueness and cost of the MJOLNIR armor itself? With the II's, the armour was costly, rare, and highly advanced. There's almost no sense for that in the IV's - with 'red shirt' IV's dying everywhere, then what, is the armor cheap and expendable? Or do they actually care heavily about the loss incurred, not only with the individual (not as significant now as with the II's and III's) but also with the specialized armor?

It used to be that the Spartan individual was a highly specialized and trained human, put together - because they were the only ones who could handle it - with a very expensive and highly advanced suit of specialized armor.
Now, it's like they can pick up new individuals from most anywhere if they seem capable of donning and managing a slightly advanced piece of armor that can be replicated and replaced if necessary if they die in the battlefield.

The dudebro spartans feel less significant as individual soldiers, both by the persons' selection and the perceived value of the armor they wear. They're more like advanced soldiers than super soldiers.

It's a downgrade in exchange for quantity, which is very different than the reason and method Spartans were initially created.