Plus Terra's heart was fine enough to with Xehanort for control and converse so I doubt the LW has anything that Terra absolutely requires. But I do agree it'd be a cool scene and resolution if the LW suddenly popped up and helped restore Terra during KH3. Just imagine a scene of a final battle when it suddenly appears and manages to save Terra unlike years prior. Then as Terra is restored the LW just falls back to the ground as lifeless chunks of metal~
This.
To be completely honest I do not know if I should be amused or roll my eyes at these constant, increasingly frantic attempts to somehow shoehorn extra importance into the Lingering Will by connecting it/making it essential to Terra's recompletion.
The LW is
nothing but an animated suit of armor powered by some leftover thoughts of Terra, it does not hold any imperative part of Terra's existence as a whole.
To be honest at this point I think the soul is an all but forgotten or ignored topic by Nomura. The series focus is the heart and more than once his explanations have kinda went over the western side of the company's heads.
That'd be so much simpler.....sadly from what I've seen of Sephiroth0812 and Tinny's post the Memorial Ultimanias statement of it being Xehanort in his true body hasn't been contradicted....meaning where Terras heart and body is a mystery.
Always presuming that there even
is a topic to be forgotten and ignored, as I don't really see the need to speculate and theorize about something which purpose and function is already made clear. The soul in the KH series represents the
lifeforce itself, the energy/fuel that allows the heart to control and animate the body. This explanation is short and simply to the point, something that is admittedly a seldom occurrence in this series, but it describes the function and what exactly the soul is just fine.
The Memorial Ultimania is one of the most recent materials on the issue, so it is not really surprising that it isn't contradicted.
In fact, the Memorial just repeats/confirms what the DDD Ultimania and another Nomura interview already said about Master Xehanort returning truly in his old, original body.
Something that got stated and pointed out so often has pretty little chance in getting contradicted/retconned I'd say and I sincerely hope that this one will eventually become common knowledge so people do not waste creativity by making further theories on a topic that needs no more theorizing about.
The Xehanort from the end of DDD is Master Xehanort in his old body, no shaping Terra's body to look like Old Nort nor any projected image, the whereabouts of all parts of Terra are intentionally kept a mystery.