This is a classic trope in romance literature. Its better known (and more usable) alternative is the-rogue-reformed-by-a-lady. Modern writers are fully aware that rogues don't always reform, so the alternative to the alternative is the-rogue-whom-the-lady-accepts-and-loves-anyway.The problem, as I mention in the previous post--
[Although] there is some (minor) truth to the idea that an evil thug can be faithful and decent to one person, it is just far more likely that that one person will end up dead either BY the thug or DUE TO the thug.There is one solution that retains the alternative to the alternative (the rogue-whom-the-lady-accepts-and-loves-anyway) while avoiding inevitable death/self-destruction.
All the individuals within the story hold to the same rules.
It bugs me when a romance (or musical or contemporary survivor-type novel) presents a grifting, lying, cheating, sometimes drug-snorting individual as someone who will not cause damage in a relationship. There's even a kind of implied, "Anybody who doesn't accept this person is intolerant" lecturing tone. It also bugs me when a story presents a lying, cheating, sometimes drug-snorting individual as a sympathetic character yet the viewer should be offended by their behavior anyway (like being asked to sympathize with the whiny version of Darth Vadar: Feel bad for him! But still consider him a villain!).
Let's just say--the writers seem very conflicted.
On the other hand, I have zero problems with Leverage. None at all.
The difference is a writing issue that plagued Buffy and Spike during the Buffy years. The writers presented a complete world with its own rules, then wanted us to get all concerned for Buffy--wasting away in a dysfunctional relationship, dear oh dear oh dear. And yes, unfortunately, there was that underlying lecturing tone.
Leverage, on the other hand, presents a particular world--even a kind of fantasy world--in which grifters give up lying, thieves have hearts of gold, computer geniuses can do anything, and incredibly violent men don't use guns while never being hit by bullets.
Nate is the keeper of all the worries and uncertainties of trying to turn a black hat into a white hat. Aside from Nate, the audience is only asked to love these characters in this world. We aren't asked to determine that stealing isn't THAT bad.
Nor are we asked to determine that a long-time grifter can be trusted in a full-time relationship.
The same could have been done with Buffy and Spike--as Shakespeare, that great man, managed to do with Romeo and Juliet (granted, he killed them off) and Baz Luhrmann, alone of every Romeo and Juliet director, understood:
The audience doesn't need to decide whether Buffy and Spike are good or bad for each other, blah blah blah. They only need to accept that in this world, these are the sanest people around.
It's a difficult romance pairing to sell--in large part because so many writers want to have their fantasy world AND their real-life application. But such an approach moves the writing from after-school-special to story, and that is a very good move to make.