The problem with transferring names is there are over thirty Final Fantasy XI servers, perhaps each one containing Cloud_FF7_Rulez. Maybe not that exact name, but you can bet each server has someone named Cloud. How can all of the Clouds co-exist if there are fewer Final Fantasy XIV servers?
On the PlayStation Blog, Hiromichi Tanaka details a possible solution. Their idea is to allow players to select surnames. This way common names from FFXI can coexist on a new server since the surnames will make each name unique. However, there can only be one Cloud Strife per server.