To take just one example - the scene where Barnabas and Julia begin to develop a relationship, which was never shot. That would have gone a long way to the jarring moment when Stokes announces to Julia "you're in love with him."
Do you mean the scene I referenced back in reply #61 - the scene in which Julia and Barnabas take a walk? If so, that was shot. In fact, there are many photos of it - one even in the DS Movie Book.
So many things needed to be established or fleshed out that weren't.
So many things weren't fleshed out because DC didn't want them to be fleshed out. Blood, gore, mayhem and death was quite obviously his philosophy over character development.
If I remember correctly, lost footage for NODS was found after the publication of the "Dark Shadows Movie Book."
It was actually found before.