Fixing One-Off Pokémon Evolution Items

Pokémon (never one to learn any lessons) has maintained their bad habit of creating specific items that allow certain Pokémon to evolve, and that's it! Why are there so many items in the game that have only a single purpose? So how can we "fix" these Pokémon evolutions by getting rid of the items nobody asked for, but still make it more unique than standard level-up?