Lol, I'm as pessimistic about this game as anyone but saying it will trump PoS in its [censored]tiness is just exaggaration. From what we've seen it's going to be Fallout 3 with voiced protagonist and WL2 synths and evil Lyons BoS. Even the parent - son thing is reused from F3. It's barely gonna be any different. That's disappointing, but if F3 wasn't a burned game then neither will this be one.
More than likely because he will be scripted to die at some point in the MQ - possibly a reference to how the canon Vault Dweller's Dogmeat died at the Military Base.
Also, I'm gonna be a casual peasant here and say companions being essential is the right thing to do. Companions being able to die is what always put me off from NV hardcoe mode. I wanted to do their quests, but they were almost always absolutely useless in a fight.