You see, the issue with only doing world transfers is that after the people on the dead servers leave for the populated ones, you'll have a bunch of servers with ghost-town populations and most importantly, a database full of dead/empty accounts. Sure Square gets some money from charging their world transfer fee, but after people leave the server, the already desolate population of that server will become even more desolate which may make more people want to actually stop subbing (instead of transferring out of the server). Furthermore, Square will have to continue running those servers just to upkeep those dead/empty accounts. e.g. As long as there's 1 or 2 people playing on those servers, the server will have to be left on, which doesn't sound like a terribly efficient use of company resources.
A server merge, on the other hand, will help consolidate that info so that it's stored on one server instead of two and will allow SE to save on operating costs. I can't think of a "perfect" way to do the merge without pissing people off, but it sounds like regardless of if they do a world transfer offer or the merge, there's going to be huge cons for each option. World transfer option for ALL worlds = people even on the mid-size worlds will transfer over to the already high-pop servers, making the server population balance even worse + wasted resources maintaining servers with already low populations. Forced server merge = bad PR for a game that already has horrible PR + risk of pissing off players who didn't want to move anywhere. Not doing anything = huge risk of losing server populations on already desolate servers dropping off after subs hit = more potential customers lost = less money for Square, but less of a chance of pissing off the people who are playing on those servers.
Sometimes, you just can't win.
