One issue that has plagued the Survival community is the unstacked mob skulls used to craft Spawners. This suggestion is to alter the recipe, thus altering the item used to craft them. Instead of the mob dropping its skull, it should drop a 'Spawner Fragment' respective to its spawner. For example, a Zombie has a (3% chance with Berserk III) to drop a 'Zombie Fragment'. These Fragments will act identical to the currently dropped mob skulls - the only difference being that these items stack. Since this item, such as a Prismarine Shard, or Prismarine Crystals (Prismarine Shards may be a problem because they can be sold in /shop) doesn't rely on a skin to differentiate it from another, they can be stacked. This also means they can be easily sold with player chest shops. Not only will Spawners be easier to craft, but it will be easier to store, sell, transfer and buy Spawner ingredients. To further differentiate this item from its true version, it should be enchanted to create a unique item ID that cannot be replicated. This item will also be filtered like normal with hopper filters, just like it does with mob skulls - one head will filter all heads. In this case, one Fragment will filter all fragments. If this were to be implimented, it should come with a converter to change mob skulls into Fragments. Hopefully, this is a solution to the issue described above and will be implemented soon. Thank you for your time and consideration of my suggestion!