Something to keep in mind is that in some cases the Pokemon may appear to be very similar (like how every early-game bird is a...well, bird), but they're individually based on different species of animals (like pigeons, owls, swallows, etc.). It's like the difference between Stantler and Sawsbuck. So the argument that GF is recycling the same species of Pokemon to fill different roles like early-game bird or token Normal type is largely false. They're recycling the roles themselves. Very, very few bases for Pokemon overlap. Pineco and Burmy are in this category, but wouldn't be if Pineco's classification was something other than "the Bagworm Pokemon" since the bagworm part is hardly noteworthy.