Vanished Pokémon Features that MUST Make a Comeback!

In a multiple decade franchise you're bound to drop a few things from the olden days, but Pokémon shuffles things a LOT between generations which means there are plenty of features that have disappeared with no explanation. So while we can mourn our favorite lost aspects, let us also have hope that they might come back and look into what missing Pokémon features need to make a triumphant return!