MARK 8 and older firstborn armor, not just helms.

We need the older first born marine armors and yes it’s been said that primaris don’t wear this armor however you could just add the option to be a firstborn marine for each class ( something akin to halo infinite armor cores). 

And if the excuse is that each class is already their own character it’s been pretty widely seen that people care much more about their ability to customise their character than in mission voice lines and stories (also I think I heard that there wouldn’t be any story dlc so this makes that matter even less).