"We don't want the fans to wait."
Fans: WE WILL WAIT IF IT MEANS WE GET ALL THE POKEMON!
"Well it is balancing ..."
Balancing what? People who play competitively? That is a small number of your fans. There are people who have beaten the league with only Magikarp legitimate. People want to be able to play the game with their favorites. I remember in later playthroughs of games I would transfer in some no regional pokemon in eggs to use as my team. It was fun, it made it feel like I was a visiting trainer rather than a native one.
I remember playing Soul Silver using a Turtwig and a Shinx (I know Shinx can be obtain in Soul Silver, but it was still fun). I brought in a Bulbasaur to Hoenn.