Isn't that why they removed the ability to kill off/abandon companions in the first place? Because people would do it then turn around and go, "Oh my God! I have no companions! Bioware, how could you let me do this! Give them back!" .
Actually, I believe in an interview with a Bioware employee, they said exactly that.
They found the playtesters, when given the opportunity to kill their companions, would take them, if just to see what happened. And then suddenly they had, and now they had no healer.
That's fine in an offline game like KOTOR, where you can just reload the last save if you gakk up too severely, but in an MMO? It basically meant that, via dialogue choices, you could permanently and significantly cripple your character's ability to progress, and diminish your gameplay experience. Nothing else in the game has that permanence. Don't like you alignment? Grind diplomacy. Specced wrong? Respec. Dump Quin out an airlock?... well, have fun with that...
The only way to make that work would be to allow you to 'draw and discard' companions, so you could replace ones you lost from an available pool. But that would hugely complicate the system, and make it tough to balance, and doesn't address the issue of lost forever companion questlines, as well as require a huge amount of recorded lines.
So, it was easier to just avoid the issue, and not indulge our jerkass impulses to this degree.