No, no, no......NO.
That's again lazy story-line design. Although, they shouldn't be party members, they should still play a vital role in KotOR III. Give them male/female voices (it doesn't matter in the long run if a few people think that they're not the "right" voice), so the main character can interact with them about their agendas. I wouldn't mind if one or both of them die during the course of the game, as long as it's in a blaze of glory, which they clearly deserve.
Nothing would be more irritating than reading the first sentence in the opening credits as:
"Star Wars: Knights of the Old Republic III"
"Revan and the Exile died during their campaign in the unknown regions. Now the Republic is at stake blablabla...".
<{POST_SNAPBACK}>
Agreed.
As somebody who likes to weave stories himself, something like what Paladin has suggested would be somehow...unforgivable. Why go through all of that, just to have both characters you played for hours and hours in the first and second games die within the first ten minutes of gameplay?
That's just ludicrous, not to mention sort of insulting to the people who came up with both characters and wrote out the scripts in the first place.
I like Mesh's idea the most though, it's got an air of KotOR about it that I really like...though a few alterations wouldn't be too bad.