I'm not an economist but I have taken senior level economics courses and the way they keep using economics as an excuse is frankly bullshit. They keep throwing this out as the reasoning behind their heavy handed way of dealing with things as if everyone should just go, "Ah, yes I see."

Not only is economic impact not a valid reason to restrict server transfers, it will also likely lead to more economic instability in the long run. Given the inevitable destabilization caused by large numbers of people moving between worlds putting off legacy transfers to a later date will just cause a second phase of economic chaos whenever they decide to allow it. Square Enix either needs to hire a real economist or two to handle their game à la EvE or stop feigning knowledge they apparently do not have.