This is wrong actually. The localization was planned as early as the NA one and it was supposed to be published by Atlus and be released in a special edition with mini-soundtrack like the NA one, as announced way back then.
The whole blame falls on Atlus for being a terrible publisher and Sega for being even more terrible and doing nothing about anything concerning Atlus and Europe even though they are the parent company of Atlus for a long while now.
There is no actual localization. Atlus is using the NA version for the European release, and it all indicates to a sloppy job that still takes too long because of their incompetence.
Further highlighting their incompetence is the fact that even though PQ is yet to be released, Sega does nothing about it and NISA had to be the one to publish it even though Atlus now does have a publishing branch, that of Sega. Before anyone says that Sega's Euro branch isn't strong, i see they are ok publishing P4AU, so that ain't true either, Sega just doesn't take any risks.
Also Atlus, as a developer are fairly competent. Don't sell them short because their publishing branch are total losers.
Also want to remind everyone that the internet was way too happy when Atlus was bought by Sega, because they were petrified they might had been bought by Nintendo. Well here goes your Atlus guys. Even worse than it was before.
Still buying SMTIV day one, still have a huge amount of respect for Atlus as a developer, but as a publisher they are just as bad as ever, and Sega, my childhood god is entirely dead to me.