The problem with Pokemon is that it already reached it's maximum point already. Once you reach such level of perfectness, there's nowhere to go but down. The only way to get Pokemon to be as popular as before is by coming up with new ideas. Trust me, the more they add more Pokemon and just throw an RPG with the usual storyline(You get to choose one of 3 Pokemon that are always the same types, you suddenly have a rival that will choose the one stronger than yours by type, you go to an adventure and collect 8 badges then go to beat the elite four, and on your way, there's some evil gang that you have to beat(Team Rocket/magma/aqua)). Okay, we already got that. It's always the same thing, and people are getting bored. They liked it before because it was something new and unique, but it, like pretty much everything else, got corny at a point.
Sorry if I sound harsh sometimes, but I was abused as a child and the way I cope is by expressing myself through my writing. Please be more understanding :(