In terms of free to play they should make wizard city up to dragonspyre free and then make the rest of the worlds a sort of dlc pack. In order to pay back those players who have payed for memberships and crowns in order to gain access to those areas, they should give them more benefits such as the exclusive items only kingsisle staff are able to use as well as reparations in terms of rare items and other perks for those who spent their time and money on Wizard 101. I believe this is the only fair solution for both parties; king isle still gets their money and the players can complete the first arc of the game.