Well, all the scripting, plot-writing, and animation stuff the team was doing, so I would assume that that means its not impossible, just very hard and time-consuming. I do understand what you mean, that it sounds like you just be creating a whole new part of the game with nothing to start from, but the M4-78 team was able to at least start to do that. As I said, it would just take a lot of experienced people with time that they wanted to devote to it.
As for voice-overs, what in the planet needs a voice-over? I thing Vash has some voice-overs in there, then Kaah needs some (but if you had to you could make him twilek - I mean, would you care if someone finished the mod and Kaah just used the generic alien voices? Maybe it could be added on later, at most, since it really isn't that high of a priority). There's droids, I guess, but maybe only the central droid would speak english. I really don't know about all the plot and everything, so I'm just quessing as to the characters, of course. And whatever else you needed could be done.... I dunno, is it possible to chop existing lines and words apart and put them into a good sounding line in the game?
No, its not simple, I agree. But one of the things that Pavlos said was that hardly anyone in the team had KOTOR modding experience (unlike TSLRP). If you take some good, experienced, KOTOR modders, or at least have some of their advice. A new team would also be started with some of what the M4-78 team did, and they would also have the benefit of learning from their mistakes - and taking Pavlos's advice in his first post. With all that, you have a smaller chance of falling apart and not completing the mod like their team did.
Besides, many people are still connected to the KOTOR series; there's a huge gourp of fans waiting for a KOTOR III, and people (including me) still play KOTOR and TSL. As I said, a huge community would come back if this mod was completed, and got a chance to play TSL the way it was supposed to be. Its not that old of game - but its getting older as we speak.