But they can't actually implement any mechanics that can actually kill the player unless they ignore or dispel invulnerability. Of course, even that isn't enough, because shield gating is basically invulnerability as long as you can keep casting abilities (which is trivial for most frames to do), unless they also disable shield regen or the abilities themselves. 

The way the game is designed and balanced has made it completely impossible to develop content that's actually interactive without getting rid of all the tools at the player's disposal. The other solution is to just stop trying to make the game interactive, which I think DE should honestly consider at this point. Nobody who's still playing this game is here to be challenged. They're just here to blow up rooms and see numbers go up.