Since the little cup is a thing and I can’t deny I LOVE to play with baby pokemons. What if a baby mode was created capping all pokemons of the game to lvl 5, the only downside to it would be that it would require a bit of time to change all the abilities from trainers that are acquired after lvl 5 outside from breeding or “de-evolve their evolved pokemons”, an other solution would be to let them intact but still cap them at lvl 5 for extra challenge.
In any case it would be cool to have that feature, or at least a little cup tournament available in the game and a specific way to cap our mons to lvl 5 easily.