I have to wonder how long Regina and Rumple can keep on the right track if they both stubbornly use magic as a crutch. And while they may think they can harness their magic towards doing the right thing, I believe it’s impossible for either one to do magic without giving into a lust for power and domination (which is what dark magic seems to be vs. light magic which is protective and selfless)
Prior to becoming the Dark One, Rumple thought he could use magic for good. Once he’d murdered Zoso, however, the magic consumed him to the point he was becoming worse everyday, just as Baelfire feared. So, I really think the only way Rumple could become the same good man he used to be is 1) Tamara zapped him with his taser so that he lost his magic (but survived) 2) He went to live outside of SB where there is no magic or 3) Rumple and Belle return to the EF where TLK can break any curse.
As for Regina, the path could be easier, and yet harder simultaneously. She isn’t cursed to do dark magic like Rumple is, but that also means she must willingly choose not to do magic anymore. She can’t just receive a TLK and be freed the same way Rumple could be. I suppose she could always willingly wear one of those anti-magic bracelets that Greg put on her before. Or she could go live outside of SB in say, Boston. That way, she couldn’t use magic, even if she were tempted to do so. With Regina, I think it’s the magic which is an actual addiction which is hard for her to give up, but as long as she’s abstaining form it, there could be real lasting reform for her. The longer she goes without out it, the more she would recover the real Regina, as she put it.
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy