I think that in Sinnoh, it would actually be a good time for the anime to end. Satoshi has progressed very far, and for once it's pretty sure that he'll attempt to challenge a Champion.
He CAN'T deny the title of Pokemon Master once he's beaten Shirona, and the anime has seemed to lead up to this so far. Also, I think the writers are doing a very good job with the stories so far, a last spurt?
The games will go on. The games will add new pokemon as they add new regions, and who said 4 regions is too much? (I guess a few more if they count side games.) Our own world has more continents than that, and then separated in to different parts. I wouldn't be surprised to have as many pokemon as there are different animals in a real world. It would be a pretty neat idea to keep going and develop this "Pokemon World" as much as they can. (:O I'd like to see a game [maybe MMO?] where you could be any type of trainer you wanted.)
Now I know the anime has gone on for a long time and they would cash it for as much money as they could. I hope that they could end Satoshi's story at this good point, and then if they wanted to keep going focus on other things or people. : D Cordinaters need some more lovin'! Oh yeah, add that on the list of addition in games. "Wi-Fi Contests Please!"