I do agree I would like to play with her without sacrificing my LS/DS score. She should be able to be turned if she indeed can't be. However, it should be very difficult, or time consuming. Subtle, slow. Palpatine didn't reveal who he really was to Annakin until he thought he had twisted him, worked him over well enough. It's not that it's easier to turn Jaessa it's just that (as much as I actually like her personally) she was "rushed", sloppily or lazily written I feel. Especially considering that you spend your whole first act of SW hunting her, her old teacher, and her PARENTS down. Even if you go light side and try to spare them, you are still hunting her down. And at the drop of a hat she just jumps into being dark side and killing her master. I've not gone the LS approach to SW yet, so I don't know what LS Jaessa is really like, only you can't romance her.
Which is why for the most part I actually like the SI story a fair bit more then the SW's. But as was said in a earlier post, time will tell.