I don't think she could. There was really nothing to her character beyond being an amoral temptress, so I really have no idea what you could do with her.
Yeah. You'd have to reconcieve her character so entirely that you might as well just start from scratch and come up with a good character that has a purpose in the ongoing story.
I would think Lila being around in Dexter's life would bring some unpredictability to the show because you have to admit that she can be unpredictable at times.
Lila
was the predictable element. It was increasingly obvious as the season went on that 1) she was written to be gratingly unpleasant and then insane in that cliched scheming-woman way (the false rape accusation was a very clumsy but I guess necessary element) so the audience would be happy when Dexter killed her in the final episode and 2) she needed to kill Doakes so 2a) the writers could get out from under the whole Doakes Conundrum and 2b) so that in the audience's mind Dexter would be free & clear to kill her without seeming the least bit "ungentlemanly" (just the off-screen suspicion that she killed an old boyfriend wouldn't necessarily be enough, since we didn't know for sure and never saw the guy, but the audience liked Doakes, and he was real to the audience).
The gears behind the
Dexter machine were really showing with the Lila plotline. I know all fiction is contrived, but I prefer the curtain to be a bit more opaque.
He stays with her because he tells himself that she killed Doakes to protect his secret and that Doakes was a relatively killer himself with the number of police-related shootings in his jacket and what he used to do before he became a cop.
That doesn't work on several levels:
1) He loves Rita and never loved Lila (how the heck could he?)
2) Lila was batshit crazy. She'd drag both of them down eventually. Dexter is too smart not to see that.
3) He wouldn't respect Lila's motive of killing Doakes to protect him; if he wanted Doakes dead, he'd have done it himself.
4) If Dexter could rationalize Doakes' previous probably killings as a reason to kill Doakes, then Doakes would have been dead long before Lila got to him. The Doakes Conundrum is that Dexter couldn't rationalize things that way.