Final Fantasy XV, first announced in 2006 as Final Fantasy XIII: Versus before re-branding last E3, is "quite far into development," series producer Yoshinori Kitase told VideoGamer. I bloody well hope so. It's been eight god damn years.
It "is being given a very high priority within the company itself" and is not "in competition with Kingdom Hearts 3 for resources," which wasn't a fear I had, but maybe now sort of is. The power of suggestion. Kingdom Hearts 3 was announced last E3 as well, though we shouldn't expect it anytime soon.
Kitase also explained that while XV is not longer tied to XIII in name, "[t]he story and the world is still going to be linked and backed up by [the Fabulla Nova Crystallis mythology that underpins the whole of the XIII series]," and that the original story of XV hasn't changed. "So even though it's not necessarily the same universe or the same game," he continued, "they're all linked and underpinned by the backdrop of that legend."
Kitase also mused on the new console hardware opening up to have "battles with a lot more participants involved" and "more characters for the player to control." He also mentioned how future series entries could hark back to aspects of XIII's Paradigm system or "even deeper customisation" of something like XII's Gambits. More XII, please.