>>34743799The game stars children who go on an adventure. How would you pitch that as a villain? The only feasible option I could think of is a Digimon Emperor type which would get Gamefreak boycots.
Most pining for villain roles ends up as just the power gaming or harem building wishes of adults. Pokemon villains are poorly thought developed and you already fight and beat the most threatening forces in the world as the hero (angry legendaries).