>>37478193I had a big post typed up where I analyzed the dex order and went into detail, but really, my theory is pretty simple.
>Espeon and Umbreon were added when the Heart Stone and Poison Stone were added>Leafeon was added in as well - the plan was to introduce a whole new trio of Eeveelutions>similarly to how Jolteon>Vaporeon>Flareon, we had Espeon>Umbreon>Leafeon, and they all evolved by stone>later in development, friendship and held items were added and they sought to move away from simple item evolutions>Espeon and Umbreon were changed to take advantage of the new friendship system>Leafeon, which only existed to make a new trio, was shelvedLeafeon, of course, remained shelved until the next generation that added new evolution methods.
