6 months more or less don't matter anymore in the grand scheme of things. FFXV will forever be the game that was in development for over 10 years, anyway. If they release it in an unfinished state the damage will be bigger than if they delay and ultimately deliver a decent enough game. People quickly forget about delays and nowadays almost any big game has had one at some point, see Deus Ex: Mankind Divided, Horizon Zero Dawn, Mass Effect Andromeda, Scalebound and many others recently. You don't hear anyone talking much about Uncharted 4's three delays from Late 2015 to March 2016 and then May 2016 anymore. Or Ocarina of Time, Twilight Princess and even the new Zelda's ~1.5-year delay.
It would be a difficult decision for SE, sure, but I think it would be wise with the importance of FFXV for the brand's future. Hell, even a 2-month delay to November (which Tabata jokingly said he'd actually prefer after "teasing" it at the Uncovered show) would probably already help enough to polish a few things more and glue everything together a bit better. Remember how in some post-mortem Naughty Dog said The Last of Us was nearly unplayable from start to finish until literally the last 2 weeks or so before handing in the master build. There's a reason why crunch phase in game development is so insanely stressful. So many optimizations and things only fall into place in the end. At least nowadays you can push day-1-patches and optimize even after the game's gone gold, which gives you another few weeks.
