I'm just going to answer the topic question, because it does come up a lot more often than you might think.
From an overall standpoint, there has been a lot of character development over the course of the franchise. That said, there are characters that have had far less development than others. For instance, Ash should by all rights be the most developed character in the show, since he's been around since the beginning. But he isn't. Now mind you, a lot of this is for narrative convenience, since he's constantly bouncing between Regions and essentially resets his team each time. But it is worth mentioning, since there are occasionally episodes where he meets up with older teammates again. So there is a degree of continuity between Regions. Of course the Pokémon and teammates get character development too, though the cast is constantly changing (usually every Region at least).
Lastly, Jessie, James and Meowth (JJM). Love them or hate them, these three have gotten the most development out of all the characters in Pokémon. Usually comic relief foils, these three have far more depth to them than any other characters that have been in the show long-term (and even occasionally help to stop real villains, even if they're not as adept as the main characters). Despite their tendency to annoy me when they appear and soak up screen time during otherwise awesome battles (though the show did tone this down a bit in the fifth Gen, and we thank them for it), I still often find their subplots to be more interesting than the heroes', especially during the fillers where they can sometimes save an episode.
