Was there an iteration of Stoneplate that worked similarly to lifeline passives, meaning if a tank went down to a certain threshold of HP, they get the big shield?
Not that we tested for S14. However, I did make Mantle of the Twelfth Hour in Wild Rift as a Lifeline tank item before I left WR to come back to work on League. Based on my experience making that item in WR, I believe HoT effects usually serve the tank space better than shields for Lifeline items for a number of reasons, not least of which is that it gives tanks more power in prolonged engagements (again, similar to Jak'sho vs Stoneplate where core tank patterns are best supported by long-term power rather than concentrated momentary power - the shield is much more temporary than the heal).