If the only reason people are playing the new game is because the old one shut down, then you're not really releasing a new game; you're renewing their subscription. You should either realize that this is evil and innovate, or realize that this is inefficient and bake it in.
This is EA we are talking about. Each new release is just as likely to completely fuck up the core gameplay mechanics as it is to marginally improve them.
Actually, now that Bobby Kotick has completely destroyed everything that Blizzard stood for, you can say it about pretty much every large game development company other than Valve Software.
