>>29782332For an example of good post-game, t's look at Dragon Quest IX, a game I feel has some of the best post-game content in an RPG.
In that game, every week for a few months you would get new sidequests that followed up on loose ends in the main story, fleshed out the world, and some even gave you new party members.
Along with that there was a random dungeon generator. These had unique enemies, the best equipment in the game, and twelve new bosses that you couldn't find anywhere else. This was coupled with a system that allowed you to reset your character's level to gain access to better dungeons.
On top of that, you had ANOTHER thirteen extra bosses from the previous entries of the series to fight. You could even level them up to make them give better rewards.
And Pokémon wouldn't even need to do half of that. A dungeon generator that had an increased chance of shinies or HA Pokemon, along with a Battle Frontier with legacy battles would easily suffice.