>>47310456It's because of the color depth. Gen 2 sprites had only four colors to work with, and two of those pretty much had to be white and black. Early gen mons were designed with this in mind (for the most part) and thus tend to have simpler color schemes.
Later, the series' art direction changed, (my guess is partially because gaming technology was getting better and partially because the world at large started shifting toward vibrant colors), so the older mons were updated a bit to match. This generally didn't change too much about their normal designs as they had very well-established references, but a lot shinies got raped in translation, probably because the artists misinterpreted the older sprites' appeal and felt they needed to compensate by adding more color.
