I can see Cora locking WWW away…thus keeping Regina from her younger sister. Cora is like a Mother Gothel to WWW, not wanting anyone to know that she had an affair(with the Wizard who was visiting the EF) and had a green baby(which Rumple could have cursed for her cheating him out of Regina), and somehow WWW winds up in Oz and goes through something tragic that lands her into becoming the Wicked Witch she is today…who may be more misunderstood than wicked.
On another thought…Cora could have abandoned WWW all together who grew up much like Emma did, and we all know how much this show loves family. And considering WWW and Regina neither having family left perhaps…what’s better than to make them daughters both mentally hurt by their mother. That’s something the two sisters can have a drink over at Granny’s after their big blow out in the Spring!
+ 
= 
(WWW being the younger half sister of Regina)
Hints to #WickedSisters happening:
1. Regina stating she didn’t care if it turned her green.
2. Cora saying she’s not wicked.
3. Regina calling Lost Boys “Evil Munchkins”
4. Snow calling Cora a “Wicked Woman” sounds close to “Wicked Witch”
5. Rumple’s reference to the Ruby Slippers…(which has not been clarified whether Dorothy took them or not)
6. Jefferson trying to take Regina to see “The Wizard?”
7. The WWW having “personal business” with Regina.
8. Regina declaring that Henry was all she had left.
9. WWW and Regina can both use fireballs…a trait probably inherited from Cora who loved throwing them!
10. At the end of the Doctor: Hatter, Brains…Whale,Heart…Rumple,Coward
10. If Once is using only a little Wicked material, Elphaba’s mother Melena had an affair with the Wizard when her husband went on a trip. Melena also had reddish brown hair…like Cora’s hair. And we both know how seductive and sassy Cora was, and mix that with a suave and dashing “all powerful” Wizard from another world…you’ve got yourself a Wicked Witch of the West whose out to get her elder sister the Evil Queen because she believes that Regina got everything she ever wanted, and doesn’t understand the true sorrow her sister dealt with!
They’re practically setting up #WickedSisters to happen!
Now the question remains for Wicked Witch… “Are People Born Wicked…Or Do They Have Wickedness Thrust Upon Them?”
Skip to 4:08…and tell me if you can’t see Cora cheating on Henry Sr. with a handsome “all powerful” Wizard?
"If you go as far as you can see...you will then see enough to go even further." - Finn Balor