Well this is a little odd...I've just checked to see when The Black Cauldron got a reissue and can't find anything about it. I know it did come out because <I>I went to see it</I>!
It never came out on VHS and was hard to see, so when it came out in the early 1990s I jumped at the chance, having remembered little from when I saw it in 1985/86.
It was around the time of the Great Mouse Detective and Oliver & Company reissues, so would have been between 1992 and 1996...my feeling was that it was nearer 1996 because the VHS then did come out soon after that.
It was only a limited theatrical reissue, with the terrible poster title of "Taran And The Magic Cauldron", though if I remember right the actual film still only said The Black Cauldron. I remember that because I was worried it would come to LaserDisc and VHS as "Taran" but when I saw "TBC" on the credit I thought that at least the film would be intact itself.
The (pan-and-scan) VHS came out in 1998, but there was no widescreen LD, meaning we had to wait another two years before the Gold DVD, which used the LD master, came out in 2.35:1 (the word was that the DVD would be cropped as well until someone in the company recalled the widescreen transfer and thought they should make use of it).
I guess the sudden availability of that meant enough people grabbed it while they could and that it made sense to do a remaster on it. The anamorphic version I saw last year was beautiful: crisp image and solid but non-saturated color, and we know it's been pre-mastered to HD for eventual Blu release.
A thought: maybe the "Taran" reissue was UK/International only? I know we got reissues of lots of the Disney films in the 1980s and 90s (Snow White, Pinocchio, The AristoCats, etc) even when they didn't show up in the States or even appear on the official reissue lists.
I'm hoping the deleted scenes will be the 15 or so minutes cut originally, but still reckon they won't show some of the harsher stuff.
Here's hoping the eventual Blu disc actually realises its aimed at collectors...!