Yes, sprites are like Impressionist painting, and the smaller the sprite, the more of an Impressionist you need to be. Don't worry about clear-cut details and specificity, just work on a feel and run with that. For instance, you may want to make the vines more obvious, by thickening them and giving them body. And you could make your leaves protrude from the Pokeball instead of confining yourself to the ball's sphere itself. Therein lies the "art" part of spriting.