How do you know how far they are in development? They could've worked a couple of years on the game already. That's actually what I am expecting.
What you are describing isn't really a "moment" though, it would be a big disappointment for many if they just say: "Oh, FYI there's a new DOA in development." If we're honest, we all know that. Next year it'll be 6 years since the last DOA. They've released 4 versions of DOA5 (and several versions of DOAX3) and milked it absolutely dry with DLC costumes and characters. Most people haven't just lost interest by now, they are annoyed and haven't touched the game in a year or more, like myself for example, and I call myself a big fan of the series.
In the meantime this console generation enters its final lifetime quarter and the big 3D fighter rivals Tekken 7 and now Soul Calibur 6 grabbed all of the attention and most of the 3D fighter market share. They really lucked out by Virtua Fighter being pretty much dead and DOA not getting into gear.
They'd declare themselves irrelevant if they on top of wasting all this time also completely botch the reveal of DOA6. Tekken 7 and Soul Calibur 6 knew not to do that. DOA6 doesn't need to be revealed on a grand stage at E3, TGS or Gamescom, it might be overshadowed by other bigger games there. For example the hugely popular Soul Calibur which was a looming mystery for some time now. NEC is fine, but then the reveal has to make a big splash. No trailer, no gameplay and no screens would be missing the one opportunity they had and basically telling the world: "We are still there...kinda...not really yet...we can't compare to Soul Calibur...we really suck...but please be excited...somehow."
Yeah, no, that won't work. :/ I hope/expect Team Ninja/Koei Tecmo is smarter than that. Either a proper reveal now or no reveal at all this year.