I agree with Illucia that extending the times of the regular stuff is good to stop people from quitting the game. I've recently seen this happen a lot of times when people came home after midnight too often and can't do anything and then quit.

As for server jumping, I know a lot of people will jump as soon as the idea of merging or cross-server events are announced. These are different people than the people who quit, but they will still leave the server leaving all the whales, that would also leave and chargeback when the server is merged. (Who would want to be at the bottom again fighting overpowered people on another server???)

That said, I'm not here to tell if anyone should change the server strategy. It doesn't matter me much if they change or not. Then again, I don't get chargebacks from my banks because I don't give poor services to my customers. :)