I like the concept of having to execute key better but like many people have said you already get a time penalty for dying often because you’re running back.
This doesn’t solve dungeons like Grim Batol or Stonevault that have pretty bad walk backs. Either being able to mount or have a speed buff when outside of combat would help a lot in those dungeons.
Moreover by adding 90s to the timers, which is really huge, it will be a pretty big nerf on some dungeons that don’t really need it like Mist, Ara-kara or Dawnbreaker. I feel there could have been some attempt at balancing dungeons timer so they feel more equal.
It’s a decent change at least for now as I feel the affix might be a bit too brutal at some level, I feel a better solution would be to add a death cap like delves have and if you reach that death cap then it would simply deplete the key. You could then tune that death cap also with key level.