Hi Jim.
A very teeny, tiny, infinitesimal amount of producers and directors have any say over what the studio puts on dvd or video. Most don't have any contractual final cut over what goes in the theaters either!
If Paramount wants to put out TITANIC, then they probably have to consult James Cameron- it's probably in his contracts these days.
If not, they can do whatever they want with it, as long as it doesn't break the original production contract.
(For example, if Cameron had contractual final cut, then Paramount could not cut the film down to 100 minutes and re-release it theatrically in a special 'studios exciting edit.')
Now Cameron's a huge name. Dan Curtis is not. At this stage, he's lucky enough to even get anything produced, nevermind negotiating for points of control. It wasn't Dan Curtis' name that got the DS pilot made- it was John Wells'.
So, we're talking about a series (1991) made years before the advent of DVD and most certainly no contractual controls over its video releases (other than standard residuals) were written into it.
MGM/UA can release it in whatever packaging, with whatever extras (or not), and in whatever format they want and whenever they want. Probably the only limitation is the cast and primary crew billing on the package which may be contractual through the unions- its something agents fight for. They don't need Curtis approval, nor do they even need to inform him of its impending release.
Now, what you'll find in something like an ALIAS, 24 or LOST is that the studio will put together a package of extras and special features and work directly with the executive producer and cast to make a set of extras that all the main heads can participate and take part in. They do this for a couple of reasons - 1) these are huge shows and the DVDs will be huge sellers and revenue producers and the marketing department knows that the more bonus materials and exclusive material on the disc, the better it will sell. It's one of the reasons they call it ADDED VALUE MATERIAL and 2) the studio has an ongoing relationship with the creative people and exec producers of these ongoing series. They want these people happy so that they continue to produce successful shows that make the studio/corporation money. It's how a DVD like the ED WOOD disc was pulled just after its release, then altered and re-issued months later with changes. Word is Tim Burton didn't want one of the bonus featurettes on the disc and wanted to include some deleted scenes. The studio, obviously, wants a hit director like Burton to have a good relationship with them, and continue to come to them with his projects, so in this case they were williing to bend over backward and pull the current disc, make the changes and re-author, repress and re-release the disc just to make him happy.
If Dan Curtis were to call MGM/UA the day before the 1991 series set was released and ask them to pull the disc and re-release it with extras, they'd laugh and hang up the phone. The 1991 series will probably do well enough on DVD, but its not going to be a huge blockbuster seller and its not a major release for them. Just another catalog title to put on the market for a small revenue return.
MGM may be attempting to capitalize on the upcoming supernatural series or whatever. But it initially was put on the schedule when the pilot was being mooted last year. Jim and I mentioned to the MGM folks that they should release it on DVD back when I worked on the Burnt Offerings commentary and shortly after it started appearing on schedules...It was pulled from the schedule shortly after the WB debacle and has been off and on (as have dozens of other titles) during the Sony transition period...At this stage, they probably don't remember why it was on the schedule in the first place!
As for last year's pilot, that's a bit of an unknown. It would all depend on what deals were worked out initially...They'd most likely have to consult Wells, Curtis and Verheiden and negotiate some kind of contract for that release, and at that stage the three could ask for changes or offer better terms in exchange for commentaries or whatever...Curtis hates the pilot though, so you won't see him championing its release...In the case of Wells though, they'd consult him any way out of courtesy as in the Tim Burton example above...