>>53615348"Overdesigned" is a buzzword that means very little. I think you mean that designs are busy, i.e. has too many disjoint features which convolutes the impression of the whole, which is a thing in all art, not just character design.
For example, pic related is highly-detailed, but since all the details are relatively similar, it avoids looking busy.
Meanwhile, Mega Rayquaza looks like its features and color palettes were slapped together with little regard for what was already there, so it ends up looking busy, even though it's far less detailed
