This is, on reflection, so much work it's ridiculous, but it concerns one of the biggest gripes everyone has about DS TSL, namely convert a "good" NPC to a dark Jedi and they still yell at you when you kill kittens and other mean stuff. I dislike it immensely because the conversations you have converting them are priceless (particularly Atton's), then all that goes out the window again.
So, would a mod be conceivable that "flips" their disposition if they go dark? I would imagine that they would still react "normally" until they become dark jedi, making a nice point of no return.
Difficulties I have already thought of:
1) I know next to zero about scripting and how influence gets awarded so maybe it's just impossible, if so my apologies.
2) Even if possible, it might involve visiting every event where an NPC might react. I THINK that their reactions are based on their AI scripts, and if so it theoretically should be much simpler, but see (1).
3) Some characters (Atton/Visas) swing both ways on good/evil reactions, and that's pretty ingrained into their characters and backstories, so that leaves Bao-Dur, Disciple, Handmaiden and Mira. One could argue that the whole concept of seduction is trickery and their "basic natures" should remain intact (for example, Disciple's stated reasons for converting).
4) Voices. I haven't gone through much of the cut VOs; maybe there isn't enough material to make those 4 plausibly react well to evil deeds and poorly to good ones. Mira, for example, has a few reactions to evil deeds that seem like they could go either way. But, I haven't looked beyond her.
On a small sidenote, I also find it irritating that when I play DS I can push all of my jedi into dark mastery regardless of my prestige class, but when I play LS I can max out influence but unless I'm a jedi master everyone's alignment stops at 99, even the "good" characters. If that's intentional to have an extra perk for jedi masters, then what's the point of being a sith lord when you can have dark masters anyway? Does charisma affect this (it doesn't seem to, I pushed my charisma up above 20 one game and got the same effect)? If not, a mod to do so would make charisma a bit more useful beyond letting a LS Visas BBQ people for cheap.
Doing a mod for this would require making modifications to many .dlg files and rewriting some dialogues and you would have no voiceover. I highly doubt anyone here will want to get into this but if you want to give it a try (modifying dialogue is not complicated) we will be happy to help by answering any questions you may have. There's a script attached to specific dialogue branches that checks who is present and fires the dialogue.
If you want a complete and precise list of all the influence opportunities in the game, including the exact file where they are located, check the .xls file that comes with Achilles' complete influence guide:
http://lucasforums.com/showthread.php?t=153012)
If you want to search the game files, you can use tk102's findrefs. You'll find all the tools you need on our website:
http://www.starwarsknights.com/tools.php) and a short introduction on the use of each tool here:
http://www.lucasforums.com/showthread.php?t=143421)
Well for the voice overs, there are three solutions: either you find people who want to do it (but they wouldn't sound exactly as the original npcs), you do the mod without voice overs or you play with the original sound files (cut, paste, etc), and make new sound files out of them. I created a new Dialogue between Uthar and the main PC for Kotor 1 using this technique but it takes ages to do as you have to listen and relisten to sound files to find the syllables you are looking for with the proper intonation.