>>39519869OP here, guess I’ll weigh in too
Philosophically speaking, the entity that is Nincada, its soul if you will, becomes Ninjask upon evolution. Shedinja is an empty shell. It’s kinda like how the “real” Parasect is not the bug but the mushroom on the bug’s back. On the other hand, the Shedinja is a piece of the Nincada that has changed an manifested itself as a stronger Pokemon, perhaps the very definition of evolution. It’s kind of a partial evo, I guess, but Ninjask is the more conventional and therefore “truer” evo