>>53660448>>53656448I'm in the camp of evolution being the major hurdle, like maybe only one in many thousand Finizens have what it takes to become Palafin, with the deciding factor mainly being mental-grit, with physical conditioning to match. The equivalent of a human being that can successfully become a navy seal, basically.
Kinda like Magikarp becoming Gyarados by being tough enough to climb a waterfall—it would explain why people aren't running around with all these OP mons despite how easy to find their pre-evolutions are.
The actual transformation should be simpler, it just can't be seen transforming, so maybe the trainer has the Palafin launch a big surf attack to hide it from view, or it spins around in a big spinning vortex of water (like superman in a telephone booth) and comes out as a Hero.