Dungeon Runners controversy

Reading the forums for Dungeon Runners, it looks like a lot of players are unhappy about the next patch. In particular, that there will be members-only worlds. People seem pretty pleased That Player-vs-Player will be segregated onto separate worlds, and nobody feels too strongly about displaying the region of each game world (e.g., what continent and country in the real world the servers for the game reside on).

Since most MMOs don't have free players, most MMOs don't have to deal with this problem. Is it a good idea? Is it just encouraging elitism? Will members find the members-only worlds to be a safe haven, or something to lord over free players. In purely financial terms, will it a) not effect (or positively effect) the number of free players coming in, and b) positively effect the number of free players who become paying members? Will it keep members playing longer?