There had been rumors for a long time. Square had hinted before Final Fantasy X and X-2 HD's release that if that game sold well, other HD remasters could happen (here). The remaster apparently met or exceeded Square's expectations (it outsold XIII-3 in Japan) (here). Prima hinted at a HD remaster back in September 2015 (link) and even a FF music composer said they were working on one (Kotaku). When the composer was forced to retract what he said, people sassumed (hoped?) that Square would wait until the game's 10th year japanese release anniversary in March 2016 to announce it (the 16th, to be precise), yet that did not happen and there has been no further hints.
With such a long wait for XV, it would have been so smart to release XII HD to help tide people over, but that would seem unlikely now. At best, we might get one later on after XV's release... I don't see them announcing and then releasing a XII HD in the 6 months before XV's release.
But why is that? Why did they not choose to remaster XII and release it before XV? Why so many hints and rumors just to stop short? Are we in the same situation as with Type-0, the game essentially done but held off for some reason? Maybe they felt it would be best to focus entirely on XV instead of dividing the public's attnetion on an XII HD?
I don't know but it's certainly a lost opportunity for Square Enix.
