It feels like a small thing, but... I would love to have date-stamps inserted (or insertable) in notes files. (Another option, less robust but still workable, would be to mark passages not just having been read, but also the date of the reading.)
It is important to read scripture with an eye to the original target of the text and its meaning to that group. It is also a human reality that our reading is impacted -- and should be, I'd say -- by our own current experiences. Having dates in notes would create a tool for recognizing and responding appropriately to that reality.