In the end whatever they do will depend on the journey to reach that conclusion, how well built that narrative is and the character development and world building involved. If they make Aurene a singular pillar of the All, it better be a fantastic journey to get there because the writers will have invalidated very deeply infused plot threads from the last several years.
If another dragon dies, there should be major consequences. If Aurene can hold all magic, there better be some great writing/journeying to make me buy into the bait and switch. It’s not like I’ll quit the game, but foregoing the massive problem (need for multiple dragons to prevent the world from ending) we’ve been trying to balance will be a huge disappointment. It would just feel cheap after all this build up, imo. I don’t think they’ll go that route, but the worry is there.