Depends on what version of Harley you're talking about. The original one from Batman: the Animated Series showed that she actually did have morals, she was just totally in the sway of the Joker. Batman was able to convince her to help him more than once by appealing to her good side.
Harley in the self-titled Harley Quinn cartoon definitely has a good side, but she's also a psycho. It's complicated. Unlike her love for Ivy.
Other versions, they definitely lean in on the "Joker except a woman" angle.
She's an anti-hero more often than not now, fighting villains bigger than her. From the New 52 when she started going solo and turned on Joker (or he turned on her really), to Injustice where she was a major player in the resistance, to the DCEU where she turned against ARGUS to stop Starro which wasn't even her mission. Even in the Suicide Squad game which is part of the Arkham universe and doesn't include any kind of redemption arc for her she's still only killing the Justice League when they're being controlled by Brainiac, who is probably second only to Darkseid as far as villains go. Under duress sure, but she's doing it.
I'm looking forward to seeing how Harley Quinn is in Folie à Deux, I think she's going to be the more psycho one that pushes Arthur to further lows. It'll be great
I really don't know what to expect and I'm glad about that. The first film was absolutely nothing like I expected it to be, which is one of the things that was so great about it.
My only worry is that the original, to me, was such a perfect film in terms of capturing and paying tribute to the Scorsese films of the 1970s and 1980s that I don't know that either going away from that or leaning harder into it will set the proper tone. I'm looking forward to finding out though.
Joker was essentially a remake of The King of Comedy with DC characters shoved in.
It worked because The King of Comedy is a great film, and especially because of Joaquin Phoenix's masterful performance.
I have no idea what Folie à Deux will be based on (New York New York, maybe..?), but it looks like it'll be quite a different film from Joker (a tragic romance musical, it seems) while probably at the same time trying to touch similar themes... which would make hitting the right spot (again) quite more difficult than even for the first film...
Personally I don't have much hope and expect it will end up being a disappointment (and even if it ends up being as good as the first one it might be a box office flop due to the original audience not being into romantic musicals), but I'd love to be proven wrong.
I wouldn't say just a remake of The King of Comedy. I'd say that was the main film that it centered around, but there was a lot of other Scorsese of that era in there. Mean Streets, Taxi Driver, etc.
I could see Folie á Deux moving forward to the next era of Scorsese films like New York, New York, but I hope not because that would be less interesting to me. I think it would be neat to use the sequel to explore a different, but similar, director like Sam Fuller
Todd Phillips is not exactly an amazing filmmaker. Joker was his first film that I would say was elevated above the mundane.