>>38839029The main subtle effect is that old, OG gen1 pokemon often had more complex shapes in their artwork, but simpler color schemes. This made them both natural looking and easy on the eyes.
In later gens, arguably even as early as gen2, they started putting in more color and pattern features, and pokemon started looking "busier".
This is in addition to the other trends (neotenization and gundamization) which most people have picked up on; the aforementioned one is more subtle and I think a lot of people sort of sense it but can't put it into words.
