The only things that were changed in Titanic was the star field in the sky, removal of studio equipment, re-framing the “Left Eye,” “Right Eye” shots, making the “TITANIC” credit a bit bolder. I am not aware of anything else that was changed. These don’t alter the film in spirit at all. No VFX were re-composited, unless you’re talking rotoscoping for the 3D (which isn’t an issue with the 2D). The framing is similar and the colours, though they feel a bit fake (Hello digital grading), is very similar to the 35mm release prints, which was not the case with the previous home video releases.
The theatrical cut as is, exists on the DVD in good enough quality. HDTV versions are also theatrical. There are ways to watch the “flawed” film.
Being the perfectionist he is, there was no way JC was going to allow studio lights or wrong star field, especially after being pointed out.
In Jurassic Park, not only was the studio equipment removed, Spielberg also removed netting that held up fake leaf canopy in the “Veggie-Saurus” scene. He added a lightning flash visually, which terrifies the lawyer, making him request the guests to return to the cars. The wire that pulls open the dilophosaur’s fan-like membrane is also digitally removed. The VFX, especially the final T-Rex shot, is touched up and polished. All of these improve the film subtly. But, JP also exists in its original (debatable) version in the previous home video releases. It wasn’t Walkie-Talkies replacing guns after all.
Having said all that, I do appreciate the need to restore the original versions. Which is why we’re all here, aren’t we? Your effort is laudable, there’s no question about that.
Film prints are like time capsules that allow us to travel back to simpler and more “real” moments in our past. We wish to share these with the coming generation some day, hoping to see their eyes sparkle with an enthusiasm that used to be ours. Unfortunately though, kids today have virtually no similarity to kids in the '80s or '90s. So, we’ll likely be disappointed in that one area at least. The world has paradoxically become more liberated, yet more superficial and confined at the same time. I apologize for the philosophising.