Ok level with me if you -blam!- up on any part someone has to go pick you up there's no respawn unless someone picks you up that's normal. If someone needs to be brought forward into the checkpoint you have to go and die after reaching said checkpoint this is considering people who can't make the jumping part or most of the team is dead in hard. In hard you already can't respawn unless your a warlock and now your adding nightfall to the picture not to mention nightfall consists of other modifiers and will promote cheating or cowardice which you can't have in the oracle portion. I'm pretty sure your considering making this hard difficulty which for one basically is saying we have to do a flawless raid each and every time or else you start over. In short even though it's an interesting idea to make it tougher it's -blam!-ing stupid laid out with every detail piling on top.

More bullshit imbalance to pve?

And an even smaller fraction of that fraction means that its not even worth the effort to program these changes. Unless you are marketed toward being hardcore game (Dark Souls, for example), it isnt worth the resources to provide something for a negligible quantity of your playerbase. It's why WoW took out attunements for their high end raids. All the time and resources for a miniscule quantity of players even seeing it.