Jesse & James could learn a tbing or two from this equally disfunctional duo!
Team Rocket isn't even a bit as dysfunctional as Harley and Joker. Unlike them, Jesse and James/Musashi and Kojiro DO care about each other a lot, and even if they are butting heads, they mostly stay together and work as a team. Joker is just using Harley and in most cases wounldn't mind if she died in some brutal way. Modern Harley is even worse, because she's turned into a psycho and would kill herself, or anyone if he told her to and I don't like it one bit, classic Harley, who just felt like she could be free with him, but got disillusioned all the way. I loved what they did in White Knight. Two Harleys was a genius move (that also proves that Joker doesn't care almost at all, he didn't even notice, that it is not the same Harley).
Also, Leto Joker looks like an edgelord Joker wannabe from Batman Beyond Jokerz Gang, and not Joker himself.
Or Classic Classic Harley who was a prop to humanize the Joker without actually humanizing him. You know, make it easier for him to be in a show mainly aimed at kids. That is she'd be the butt of his jokes, without usually being in the direct line of fire. One of the best examples being the Joker fish story-line from the animated series in which she was introduced. The joker fish wasn't a particularly funny gag in of itself and the blackmail angle was ridiculous with the plot being more of a testament to the Joker's vanity, but Harley sells it because of how uncomfortable she is with the whole thing, whether singing the jingle for a commercial or physically handling the merchandise.