>>34761381Let's be realistic here. If they become a thing, they will be a one-generation gimmick mechanic, and will only affect specific pokemon.
We already have a bunch of fusion pokemon, they are just unable to fuse mid-battle.
Generation 11 will probably have a pool of about 20 pokemon that are each able to fuse with 3 other selected pokemon, for a total of under 100 forms. Only 40 of those forms will be visually distinct (the other will just be "big guy with a pokemon glued to his back/chest/shoulder") and only 20 will be at all useful in battle