What a GREAT IDEA!!!!! (w00t) I've not see that on this form yet. That would open up a wide rang of new characters and down size the ones that we never have with in are party (GOTO). :D
I'd be OK for this with one or two characters, or at least to have the choice whether to leave other NPCs on planet or not. However, I'd also want to have a core party that travelled with me wherever I went, as this would allow for deeper backstories and relationships that developed over time, and add to the epic feel of the game, something the Kotors do well.