I’m glad that Sponge isn’t using an ECS, mostly because it seemed a little silly to use a design pattern that is completely different from the one being manipulated… Although I was excited about the convenience of custom components. 
So has there been any discussion on a solution for attaching our objects to Blocks, Entities, etc? Built-in persistence like what deltahat (who wrote Bukkit’s Metadata API) suggests would be awesome. 