I liked this. The biggest thing it had going for it was the bleak atmosphere. Phoenix's performance, the direction, photography and music all combine really well to make an interesting, unique experience that for the most part overcome the flaws of the film. Which other than some clunky dialogue and plotting here and there and underwritten side characters, the main thing is what a lot of others have said, it just doesn't feel that "deep", or at least not as deep as it thinks it is. Which I know is a vague criticism, but it's how I feel. Whatever social statement the film is trying to make just feels a little surface level and at times spelled-out and blunt.
Honestly the movie ended just when I was starting to really get into it, and maybe if it went on a little longer they could've dug deeper into these things. I actually think the movie could have gone on a bit longer, and I think there should be a sequel (which the way film is performing seems very likely). The movie ends when Arthur well and truly becomes the Joker and I thought this was Phoenix's performance at its most compelling. And honestly Phoenix's performance as The Joker feels a liiittle spotty, like I wasn't quite sure of what he was doing with the voice and it felt like he wasn't 100% there yet (although thinking about it that could be true of the actual character of Arthur as well, not fully "become" the Joker yet), but it was still utterly compelling and if they (probably) make a sequel he'll really get a chance to flesh the character out and go to some cool places with it. Which is kinda how I feel about the film as a whole, it's good but it felt like a little something was missing, and I think a sequel could build on what they've established here and improve it. I don't think they need to be as beholden to Scorsese in the future, I didn't have any problem with the story elements cribbing from Scorsese but some of the overt visual homages felt a little over the top (thinking him pointing the gun at the TV). Also some better written side characters, seems like they just underwrote everyone that wasn't Arthur and then cast really high caliber actors hoping they'd seem more memorable (De Niro was fun though). Still though, I think it's commendable for a major studio to commit to something this bleak as a big tentpole release and it working out for them.
Also Not sure how I felt about Zazie Beetz's role in the film. I mean it's clear as day she's in his imagination, I don't think the movie is even trying to hide that fact. I don't know, just felt weird and I wasn't sure if that story element worked for me or not. And I think they left her fate ambiguous in case they do make a sequel. I think killing her off would have been a ballsier move though and the logical progression of his character.
ALSO Lowkey first trailer is better than the movie, and I kinda thought it would be. I mean this trailer is incredible and basically takes you through the whole arc of the movie in 2 and a half minutes
And Heath is still the GOAT Joker