Let there be no more doubt that he is at least waying his words. He is no longer denying that he has something to hide about the concept. What that MISSING stuff is, be it b/w Alien 3 or simply the stuff the series never wrapped up, or possibly both...
Probably elements which have been missing in the recent films. It's a theme he keeps reiterating in interviews.
Psychosexuality, biomechanical aesthetics, making the project a genuinely horrific
viewing experience... A proper return to the derelict's chamber/cave... Agony of egg transformation - hopefully. Might also be something like a strong hint at a Giger-like world where the Alien originally came from.
In fact, if Weyland-Yutani got ahold of the/a derelict and
a Queen Alien, trying to figure out where the species came from seems like a common sense move. They'd be eager to exploit any new such technology. Especially if the ship in question is mostly in a state of irreparable damage; it could teach them a lot, but not nearly as much as a fully-functional version.
Basically, it's probably a wish-list of all the stuff which tends to hit you in the face when you open up a really good reference volume on the films. The stuff which makes you go, "Darn... Wish we had been given more of X, Y and Z."
It could also include a much better look at the Colonial Marines, if they're included in the story - or at least, the type of military hardware they would use. After all, in 'Aliens
', all we saw were the equivalent of a recon/repair team. A fully
outfitted fleet would have some seriously imposing capabilities. Especially if a rival group/government intervenes with an interest to take advantage of whatever Weyland-Yutani have possession of.
Ripley might get to "fry half a city".