I have to disagree with you Leafsdude.
Your first argument is that people are going to want to play the updated world and that the demand for the "old worlds" will be limited. My counter is that you are asking for it because you want it; if you want it, it's easy to assume that others will want it and that there is a demand for these worlds to stay. You don't need to look any further than this thread in order to find people who are upset that the game will have to cost a couple bucks to play or that a reset is probably going to happen and who would probably stay in the free worlds. And then consider that most players would rather play where most of the community is located and you've got potentially a large amount of players (my guess is the vast majority) that would stick to the current worlds even though they wouldn't have all the cool new features. That kind of situation wouldn't at all address the current reason why the staff want to add a cost to the game; it costs money to make and maintain the game and if they don't break even or better, then is it better (for the staff) to keep this game running or shut it down?
I do have my doubts about how many new players the current trials can attract in order to keep the community big and healthy as people are stingy about small amounts of money, but there's no way to know for sure until everything comes to fruition. I also hope that there will be a way to keep managers around who are unable to pay, whether it be for age or else severe financial hardship, but then how do you verify those types of things?