Now lets have the fake hope that the Night Elves are going to get some positive development and not just another arm cut with a band aid as the reward again.
I would just go with the Night Elves finding a way to "Exchange" souls, and basically every now and then the NE people just exchange their life with those in the Anderweald, and become a true master of the process of rebirth and part of its protectors. That would be a nice "upgrade" to their culture, as in the end, as long as the NE race exist, none of them truly die, basically another version of what they used to have prior having the Druids wake up from the Emerald Dream in WC3.