The good:
-Margot Robbie was a very good Harley Quinn. The whole mix of funny, sweet, and outright harmful violence she inflicted sold the mood of the Joker well.
-I liked Leto overall. I know this is a crazy statement, but his presence in the film was almost understated. The movie was never about the Joker, and his actions were quite coherent. I think the menace of the Joker was well conveyed throughout, without him seeming implausibly important in a war of gods and monsters.
-Enchantress and her Brother felt like ancient god monsters. Overall I felt they were rather well done villains. There was a coherence, logic and theme to their threat and I enjoyed it.
-Waller was Annalise Keating and it was awesome.
-The film felt rooted in context. The world felt living and breathing, tied to things, the characters seemed to have internal lives and histories. For a film like this I think it accomplished a lot in claiming there is a DCCU that can be cared about.
The bad:
-Will Smith played Will Smith. This was almost certainly necessary, because the rest of the cast was some combination of taciturn, unpleasant, crazy and evil. Will Smith however was one of the least coherent characters in the story, with Deadshot whitewashed too little to matter but enough to be annoying and having far too many heroic impulses to make sense. I think if you had actually made this a fusion with Hancock or something and let him actually play the grumpy whitewashed Wolverine the movie would have improved dramatically.
-The editing was weird and so was the pacing. I think it worked in some ways, but was overall a huge net negative.
-The government agents did not sell that they were good enough at crazy herding to keep this together OOC. "If he dies, you die." How is that not an invitation for Harley to maim him and act innocent immediately after? When Waller was on screen it was even worse there.
-The final fight really didn't work. What, random bomb takes out a medium rank god? Will Smith's bracers did shit? The emotional arc really didn't sell that Harley liked these people specifically, so "you hurt my friends" sucked even though Harley walking up and cutting out a heart should have worked very well.
-It was just a mess overall. A lot of complicating factors wore it down. I think the movie was legitimately more than the sum of its parts, but a lot of those parts were just pulling it down.