What does M4-78 add to the storyline?

I read this thread before I started Kotor 2 and decided not to install it. After having finished and watched some youtube vids on M4-78, I'm glad I didn't play it. It didn't seem to add anything to the story except the obvious difference in the original game.

That's rather a personal issue: I always visit Korriban last, so M4-78 doesn't fit into the overall storyline or progress, it feels "added" at that point, near the end of the game.
Also, while the quests, dialogue and design of the planet are fine, I didn't find them to be as enjoyable as I hoped.

In the rest of the game, I think the authors tried very hard to limit the shuttling between remote quest points. On the botworld such shuttling was emphasized by the authors. This made it seem different to me from the rest of the game.

Also, though it's probably not the authors fault, the stupid bot names were impossible to keep straight. I made mistakes and headed for the wrong bot several times, which increased my shuttling.

The Exile not dying in the end, is this to do with the force bond? I don't think that was explained in my playthrough.

That's cause Vash tells the player why, and that was cut from the main game...

Thanks, I will google for some playthroughs now...