I think Dr Leland should've been in the Enemy Within.
To clarify I'm aware of the theory that John killed her. I don't agree with it and let's just leave it at that.
Now that the season is over I really think that Leland should've been in it. I just think it would've been really interesting as it seems that in some way that John felt some kind of attatchment to her. He constantly talks of her and reminds himself of certain things she told him that I think helped to keep him somewhat sane for a while. Plus in season 1 it seemed hinted at that she liked him. I like to imagine how she must've reacted to seeing John on the news when he was a Villain or a Vigilante. I think it would've been interesting for Bruce to see her so we could try to understand John and talk of his attachment to Bruce. Maybe we can see her again in a future season.
Please share your thoughts. 
Comments
I agree! Why do people think John may have killed her..? Wouldn't make sense really.. I really hope they make a third season and that John's in it too to make this possible. Would be so interesting to learn more of John and to hear Dr. Leland's thoughts, and see them interact.
I believe the theory came from the Villain route as there's a scene where John talks to Leland as if she's right in front of him and some people think there's no way she would've authorized his release, but like I said I don't agree.
I think he was still talking to BRUCE and accidently called him "Leland", because in his mind Bruce represents her in some twisted sense. Bruce is a lot like a guide model for him outside of Arkham, much like Leland(aka authority figure). Much like Harley. Joker's mind slips. Since his "awakening" after memory loss he was basically raised in mental hospital, he used to look up to some of his doctors, Leland in particular. He's looking up to Bruce advices in a very similar manner.
Bruce Wayne, therapist of the year.
I'd love to see her reaction. I was wondering a lot, what it would be like. I believe she won't be very happy with Bruce. She suspected he was a bad influence since his first "visit" to Arkham. Didn't like him a lot.
And look what happens.
We'll probably see her in season 3 (if season 3 happens), if story somehow will demand Arkham scenes or Joker interations.
But with what happened to Mori and mr Freeze nothing is ever 100%, lmao.
I think Leland's problem with Bruce was more that she could clearly see that he wasn't well and needed help but he wouldn't let her help him, rather than being a bad influence on John.
It was a problem.
But she also comments about how only one day in Arkham with Bruce ends up in a riot. Commited by John. And Bruce.
And after Bruce and John spend some time together outside of Arkham, John returns back to Asylum as Joker.
Leland is a doctor, she can connect dots.
I think Doctor Leland will make a reappearance in future seasons.
An I have to be honest and say I don't think her appearances will have anything to do with John.
The woman struck me in season 1 as being rather arrogant.
She doesn't like having her expertise or authority challenged and she seems to think she knows what was best even when it is proven that she doesn't (the fact she released John when he clearly wasn't ready for it proves this)
I can't help but wonder if maybe Leland will follow in the footsteps of Harley and become a villain not a crazy one but still a villain none the less.
Then again maybe she won't become a villain but she could still be a major pain in the ass for Bruce because she seemed to think she knew what was best for him and that he needs help and treatment etc.