To be fair, Gold Saucer was even locked out at times in Cerberus - a pretty low pop EU server.
Can't imagine how bad it must be in Balmung..... *shudders*

Isn't there a way to have server capacity be dynamic? So capacity shifts and expands to accommodate the needs of the game. Not many people in X-Zone? Shift capacity to Gold Saucer!!
Might not be possible, idk...