Seeing as I've received this particular request numerous times, and have not heard a valid argument to accept it, I figured I'd take an official stance, state my professional opinion, and make a final announcement regarding the subject.
Official stance: TSLRCM is the only way to get the "canon" experience of TSL that is continuous with the rest of the Old Republic storyline. Making any other claim is futile.
Professional opinion: TSLRCM is a requirement to enjoy TSL at all. It's very existence is not only the reason mods like PartySwap exist, but also the reason why making them work with the game was relatively easy. Anyone who doesn't use it does themselves and the game they're playing a great disservice.
So here's the announcement: A version of PartySwap that works with non-RCM installs of TSL will NEVER enter development. Along with the statements above, to do so would be to also subject myself to replaying an inferior product for the purposes of testing, and let's not forget the fact that I would also have to start completely from scratch, with different files, different installer setup, etc. I know of no one who would willingly subject themselves to such torture. So, yeah, not gonna happen.
DarthTyren has spoken!