Quote:
A: As I mentioned earlier, now is the only time where certain achievements are available. On top of that, we're currently working on something quite unique regarding the character's appearance. Please consider it a sign that the character has loved living throughout that era. And of course, they may be treated differently in game. For example, players' title may change as well as NPC reactions to them may differ.
By locking out character gender changing they're preventing players from carrying over these features. Someone who had started as a Miqo'te because they wanted to play a feline character cannot play as what they really wanted, a Miqo'te male, without restarting. Thus they don't get all these extra features such as the achievements, equipment only available during this era, and this appearance thing they're doing. On top of that, I believe it would also make you ineligible for the Goobbue mount they were considering.