When I was reading, this passage caught my attention when Hoid is talking to Dalinar about the Spiritual Realm. The passage is this on page 244:
To my knowledge, this is Kelsier when he gave up Preservation to Vin in Secret History. But here, Hoid says it was the "wrong" choice. Does this mean Vin killed Ati was the "wrong" outcome? Should Kelsier have united Ruin and Preservation? Should they have stayed apart? Or is it just Hoid saying it wasn't the best for Kelsier. I see two possibilities, either it's nothing and Kelsier himself would be better off as a Shard, or... Harmony was not supposed to happen. What if Sazed isn't the Hero of Ages? What if Autonomy somehow corrupted the prophecies like Ruin did in the original series? I think this is critical to focus on...