>>539149401, there's obviously some regency bias, but 2 I think you're largely glossing over important things that have changed from RBY to SV.
The fact is, when you got a pokemon in RBY, you had 2 static views of it. The front and the back is what that pokemon was. And those sprites were pre-posed renditions as well.
So the change from a Grimer to a Muk for example, while when you think back on it is mostly a change from a small blob to a larger one (still more than the difference between Pawmo and Pawmot mind you), because of the sprites being so important to how the pokemon was thought of in those earlier games, the change in pose and expression between those two blobs was huge.
And Rapidash and Tysplosion are retarded examples to pick by the way.