Star Trek VI is also extended on DVD; there are actually two versions of this extended cut, one on the single DVD release and one on the double DVD release. The Blu-Ray is the only time the theatrical version has been made available on home video, AFAIK.
Yeah you're right but I believe the changes are pretty minor. The only one I noticed is that as the conspirators are being named an image of them flashes on the screen. I prefer the original because the image and the sound effect they use really take me out of the scene.