[1] Compare https://touringinstability.wordpress.com/2013/10/18/the-alie...
(There may be specific topics where "show, don't tell" becomes "experience, don't show". And 2001 tried to accomplish this. The Abyss, on the other hand, tried still to show, probably failing in its mission. — There was a time when German media theory, in the wake of F.A. Kittler, was kind of obsessed with the written signifier of the novel giving rise to an immediate, visually representative significant. Observed from this perspective, even Clarke's novel takes a step back into abstraction: we may find it hard to invoke an immediate imaginary representation, while reading, the narrative pretty much falls back to us being told, instead of giving rise to imagination, much until the last, much more "tangible" gesture of the Space Child. But, even then, the perspective of the Space Child, cynical without cynicism, and what may come of this, is very much an open ending. So, why not move this openness forward in the plot?)
In the original cut (I saw it opening day in Westwood Los Angeles, owned the laserdisc, then some special DVD set), Russia and the USA are getting agressive with each other. The military on board, Michael Biehn, is going crazy from pressure disease and the knowledge that there is an enemy (Russia). Bud goes down to stop the bomb sent by Beihn. The aliens come up, their ship miles across, so big that several battleships, Russian and USA are sitting on top of it. The end.
The implication being the wouldn't war happen because of the aliens revealing themselves.
This is a very 2001 ending. All implication
In the extend edition the aliens show Bud videos of human aggression and at the same time make tsunamis appear towering over several coastal cities but hovering still, showing the alien power, the aliens basically saying they'll stop the war through their power. The ship rises. The end
This is a completely different meaning that might (the alien's power) gets to preach and decide. It's effectively spelled out.
The extended edition is bad IMO. On top of the long preachy ending, several earlier unimportant fluff is added that makes the movie drag