With this switcheroo, or blurring, of Hyde and Jekyll’s roles of good and bad… Could we see the same thing happen with Regina and Evil Queen? I don’t expect a full switcheroo, but a blurring would be interesting. It also could lead both of them to decide to voluntarily re-integrate, that would be I think more interesting then Regina forcing it, or them figuring out a way to kill just the Evil Queen.
The Evil Queen basically originally saw herself as betrayed, and mis-understood, and having such feelings can be normal and even healthy. Along with the pain of loosing a loved-one basically under the direction of another loved one (her mother). Where she went over-board was when she decided what revenge/justice for her looked-like, and the lengths she went to try to obtained it. Maybe the Evil Queen is still that person, but maybe her revenge doesn’t look the same as it did before. Heck, her revenge could be aimed at her ‘better’ half for doing this to them.