Not sure if anyone's thought of this.
Some people, I don't know if many, might've had a problem when linking their SE account to the PSN account and so it goes for the game (since it registers itself with the SE aaccount).

Rather than to link the PSN and SE account together. you could link the Game itself(FFXIV: ARR) to a PSN account allowing you to enter with any character only if that PSN account is registered with the game despite the SE account to log in so we'd have the chance to use an account of ours or anyone (friend or familiar) to play on that psn account only with any SE account they got. At first to use it with the first one you registered your game with and allow you to use another only if (that another) have the security token activated.

Security token changes it's password every certain amount of time so I doubt anyone would be able to hack it if you can enter using a different SE account with the only condition it must have the Token.