Jade Cocoon would let you turn your monsters into silk, which killed them but allowed you to sell the silk for a high price. Stronger monsters and especially monsters you trained yourself would sell for a higher price.
Imagine a Pokemon Breeder area in a game, where customers will ask you for specific Pokemon ("I want a Modest Exploud with a SpAtk IV above 25") and paying you or rewarding you with rare items and Pokemon. And even beyond that area, being able to sell your junkmons for money or even selling for tokens (like BP) to buy useful items would be great.
Also I'd love for Pokemon to have the same amount of love and attention that other, smaller franchises pour into their games. Just comparing Pokemon to Digimon or even Youkai Watch in recent years is depressing.
