Does remaking the existing modules may didn't work for you? Just my 2c -- I think everyone be better off remaking the existing modules rather creating new ones, at least with resources/SDK that we had for now. I mean, modules not only about models and textures -- there are also lightmaps, paths [in PTH format if I recall correctly] and many other details that's close to impossible not seeing the day-light to create from scratch -- that if the goals actually to make them functioning in real-time, rather than only for display/proof of concept.
Take this one for example. That's a reskin of RedHawke's ORD Mandell Mod. From what I see, it looks decent enough for a new planet, without having the feeling like it's a straight copy-paste to Dreshdae. Another outstanding example is this one by @Sithspecter [excuse me for using your post as a reference, SS] --
-- if I haven't told that it was a reskin of Manaan's Sea Floor - I wouldn't have guessed, really.
Edit: another great example of reusing modules is @jc2's Lehon Mandalorian Expansion. He's remaking the Rakatan settlement as the Mandalorian stronghold in his mod. Though aesthetically look the same, other than that everything looks different with smart replacement of NPCs and placeables. Though locally I did modded the looks of the module, so it looked like this --
-- and that's only changing the skyboxes and the flag's texture. Not yet involved with lightmaps, AuroraLight and fog.
TL;DR -- there are much more important things rather than fiddling and getting burned out with newly created areas/modules; such as gameplay, storyline, characters/NPCs, voice-overs and audio [BGM, SFX] are elements that can make a reused modules feels unique and fun to be play with. I mean, big name developers are also known for reusing their assets far as I'm concerned, hahah.
Edit2: what I'm trying to say above was -- it's not entirely impossible, only it's a pain to do so. At this point we may have to reflect at Canderis' post above. Also I seemed to forgot that you were talking about doing a "KotOR III" -- I thought it was about new modules, even more a new planet that already send chills down my spine, hahah.
I hope that can be useful -- since you asked for feedbacks.
P.S. hope that I can contribute more on this one, but since I haven't finished TSL yet think I'm stuck at technical areas for now, lol.