I think there are degrees of evil and that in the end it’s the actions one does that show who is really evil. When Rumple first became the Dark One, I think he was set on path to become truly evil, until he lost Bae and then it became all about finding his son. I’m not a parent myself, but I know my mom would move heaven and earth to find me if I was “lost” so how much can we honestly judge his actions post-losing Bae as “being evil” when it was done in the name of parental love? He does do some good, even if it’s for selfish reasons, he does reunite Snow and Charming, he grants Cinderella her wish of escaping her life, and he did end the Ogre War.
Regina, like Rumple, isn’t 100% evil either. I always went back and forth on how she felt for Henry until “A Land Without Magic.” I do believe she truly loves him, she is just a very warped individual, intent on keeping her control over the world she and the Dark Curse created. And she has done some pretty bad things too: enacting the Dark Curse that punished more than just Snow and Charming, killing the Huntsman, trying to poison Emma. But we’ve also seen that long ago she was just a girl in love with a wicked mother (now THAT woman might be pure evil…)
I think what will be the true sign of “evil” and redemption (which I’m sure will be a motif throughout the rest of the series, just as it was in LOST) will be what actions they both take from here on out. Will Rumple still the guy who makes bad choices, even if it’s the name of love (for Belle with the Wraith or for Bae and whatever his plan might be)? Will Regina be so focused on keeping her power and control that she destroys more lives?