The server structure atm is kinda busted, but not all that different from most games(MMOs), which is to say that

Each world is a grouping of servers those servers broken down into smaller groupings for each nation and each nation grouping broken down further to support specific areas. The flaw is in the load balancing that's apparently not present.

In a decently structured server farm an area under minimal usage would share it's resources with high usage areas i.e. Mor Dhona Machines give Ul'dah machines some support to offset the absurd loads on them. For all intents and purposes the servers in this seem to me to be dedicated strictly to a single area w/ zero resource sharing/load balancing.

The devs would know more/better, but I'm fairly certain I'm not off. That said, if a machine in the Bloodshore pool drops only other Bloodshore machines step up to help, overloading them causing them to fail, more drop and well you see where that's headed.

Erroneous behavior is to be expected in these circumstances.

This also means that even on less populated worlds if something causes servers to crash weird shit's gonna happen.