Also, BW has reduced the plots of an episode being based on a wild Pokemon a wide amount. It's normally always to do with a trainer and it's Pokemon, or a plot from X human character which leads us to a wild Pokemon (such as the TR Kami Trio two parters or the Cilan and Cubchoo mystery episode).
I'm not saying that wild Pokemon don't get big roles anymore, but if they ever are the main focus it's normally because of X human character doing something to disturb them etc.
The last time we got an episode where the main focus was the wild Pokemon alone was the Onix Island episode. Before that it was the Durant episode.