Or can they at least be downed in Normal mode? One thing I can't stand is invincible companions. But I don't like losing them all together unless I'm playing hardcoe. There has to be some punishment in place to force the player into a bit more tactical decision.
Hell, my idea of a punishment--this is of course the AI and player control of them is good--is to make items on the companion lose durability as they are downed (which I think Fallout New Vegas did but cannot remember), and have them risk losing a small percent of consumables. Could be 5% of ammo and a 20% chance to lose 1-2 pieces of materials and consumables (applied individually to each stack though). Could go further and have a 30% chance that items with 0 durability could be destroyed.
Again, this is assuming AI isn't completely moronic AND the player can maintain the basic controls such as 'attack' and 'stay' lol. But this allows for interesting builds now (compared to a more linear that other fallouts may have). You could focus on a tanky companion that goes balls deep but don't allow him to carry anything due to the risk factor. Or have him as a 'backpack' and focus on keeping him out of battle and supporting you from afar.
You can even create items--say a necklace--that specializes the companion even further.
Have a Juggernaut necklace: 15% more health and health regen, 10% increased melee/shotgun/heavy weapons damage, but 100% increase loss in items and 20% increase loss to durability if downed.
The Hoarder necklace: 15% increased backpack size, decreased chances of durability loss and materials/consumables lost if down; But 5% slower and 15% less health and armor. HELL, let's go further: The Zombie necklace: 15% increased movement speed, 25% increase attack speed, attacks poison targets and regain health per hit, melee only, and is highly aggressive (cannot control). But cannot carry or wear any items except melee items. (robots cannot wear)
The Sniper necklace: Lands 100% of shots critically with long ranged weapons (dictated by scope) but attack speed is lowered by 50% and has 25% less health.
Robo Dog: Dogmeat can now be outfitted with a ranged weapon, has armor, and feet turn into jets (added it just for fun), but cannot carry anything----Dogmeat with Fatman would be a sight to see...until he kills himself or the player HAHA.
Let me know what you think. Of course, I had some fun brainstorming at the end haha.