Much has also been said about the tonal difference between Suicide Squad and something like Batman v. Superman. The former has the tone of a grown man shoving hot sauce packets into his sphincter, hoping that you'll like him. The latter has the tone of a stray dog out in the rain. The former was meant to fix the latter, and it did not, because you can't just say "That movie was too serious. For the next one, we need to put on a blindfold and shoot jokes at the dialogue."
Both of these things were desperate attempts at being "different," all in the place of doing something truly different. If they want to create an alternative to the goody-two-shoes antics that you see in stuff like Wonder Woman, they have to start from the ground up. It has to look different. It has to be shot differently. There have to be different morals in place, and different stakes. If I'm watching a movie about ultimately irredeemable bad guys, it has to be about some bad guys instead of temporarily awful bros just waiting for their chance to punch the clock and head into Redemption Land. And if it's a smaller story about characters who don't have the fame of Batman and Superman, you can't end it with a giant laser / unstoppable monster that threatens the whole world.
Make it gritty, and make it actually feel seedy. And if you want your movie about serial killers to be effective, it has to make audiences feel a little gross. We're rooting for the clown girl who has disemboweled a whole borough of Gotham at this point? Is this right? Why? Batman v. Superman actually got the tone of a perfect Suicide Squad movie better than the real Suicide Squad movie did, because the whole time you're wondering if you can really justify what Batman and Superman are doing. I'm not asking for a movie that tries too hard and gives us some hardcore Zack Snyder fanfiction. I just want a movie that is different because, at its core, it's about the villains, and not a bunch of relapsed antiheroes.