The difference between the two versions is that the Director's Edition is a mild improvement over the rushed theatrical release and a major improvement over the hastily-assembled television edit that was later sold on home video as the "special longer version." None of the versions make for a great movie, though, but that's a problem with the script and Wise's direction, and not something that re-editing the film will fix.
I sure wish there was a version that reflected Wise's more judicious suggestions for a shorter version that he made a few months after the film was released, though it is unlikely such a thing will ever be produced.
I agree with this 100%
The SLV is a mess of a cut--too slow, too padded, with lots of useless bits. There was a time I thought, "Wow a cut with every little bit included, great!"
That is something I moved away from.
The Theatrical is okay and nostalgic for me, but
a cut with nearly every chartacter bit removed. from a series that was all about character interaction???
The DE is the best cut, but is clearly not what Wise or Roddenberry would have come up with if they had 3 more months to edit the movie.
The best cut of this movie is still out there but will never happen officially.
Problem is that fans of the Theatrical and the SLV are in love with parts of those two versins and no future cut that doesn't include their fav bits, will always be inferior to them.
Worst part is that this movie could be cut to 120 easy-WITHOUT cutting any of the dialogue from the DE AND even adding a several lines cut out of the DE "command fitness!" "We all create god.."
I have done so from a laserdisc (a format which had no copy protection) to VHS tape.
It was obviously crude, but it retained almost all the dialogue and shortened many shots inbetween dialogue--longs silent pans and characterswalking about and staring.
I know nothing about editing, but I know a great editor could have given us a decent cut with almost all the character stuff that wouldn't have us falling asleep or looking at our watches.