I remember that chubby Pikachu. Looking at Atsuko Nishida's own drawings of Pikachu though, it looks like the official art is actually coming closer to how she had intended. (Contrary to belief, Nishida is Pikachu's original designer, not Ken Sugimori. Sugimori just redrew Pikachu for the official artwork.)
Speaking of which, any thoughts on the human characters' designs? I noticed that the outfits have been getting more SF-like. The original two generations had pretty normal outfits, most people having plain clothes or traditional clothes. Giovanni, being the head of a crime syndicate, wore a black business suit, for instance, and besides Misty's side-ponytail, there was nothing too unusual. Now, we got Iris, whose hair must weigh more than the rest of her, and Ghetsis, who wouldn't look out of place in a more traditional JRPG like something from Namco or Square-Enix. I have no complaints about this though--if anything, I like that Sugimori (who DOES do many human characters) is now doing a lot of designs he wanted to do--after all, look to the Pokémon movies for the truly bizarre outfits. Infi's concrete dress, anyone?
That picture of May also reminds me of something:
She looks WAYYY older than 10. Or even 12. I'm glad they're making the female characters either resemble something closer to their age (Dawn) or bringing up their age to something more probable (Hilda). That being said, I think the character designers realized early on that May is overly curvy for someone her age, and images of her, both in the anime and in the video games, had portrayed her flatter and flatter (though still with those child-rearing hips for a while) as the 3rd generation went on. That image has Jirachi in it though, so it had to have been pretty far into the generation. Maybe Sugimori just likes busty tweens.