I think, overall, I like the movie if I don't think about it too much.
There are a lot of cool scenes which are enjoyable in isolation, but the movie as a whole flows a bit oddly for me. (FWIW, I had similar issues/criticisms of Star Wars Rogue One: a lot of cool individual characters and pieces, but it's somewhat incoherent when all put together).
Thinking more, this film reminds me of a lot of some knock-off films I watched on Cinemax or on late night USA in the late 90s. What do I mean by that? Those channels would have thinly veiled knockoffs of popular movies which would be like Mad Max but not Mad Max or like Star Wars but not Star Wars... if that makes sense. To be fair, some of those knockoffs were very enjoyable films, but, in the end, they always just ended up being a substitute for what I really wanted to watch and filling up some of my leisure time until the real thing was available. Suicide Squad felt a lot like that to me. Even the main character (despite being played by the excellent Idris Alba) came across as the B-Movie version of Will Smith's character from the first movie.
It was kinda like Dirty Dozen or the Expendables, but not quite. It was kinda like Guardians of the Galaxy, but not quite. It was sorta like a lot of things, but not quite. It hits a lot of vibes from a lot of things I enjoy, but never quite fully hits the stride. Overall, it's an enjoyable movie and it does a good job of feeling as though I am watching a live-action comic book in some parts, so that's good, but many parts of it end up feeling like a lesser imitation of something else.
For me personally, Harley Quinn made the movie worse. I completely understand why she's in the movie, but she's given way too much time and it hurts the development and marketing of other characters. Honestly, I think I'm just burned out on the DC Movie version of HQ. She's not even a character anymore; she's a plot device which requires her to be a version of HQ which really doesn't make a whole lot of sense (even in the context of a comic movie). This may sound crazy, but I recently watched the movie Cruella, and I feel as though Emma Stone's portrayal of Cruella was a better Harley Quinn than what we've been getting from DC Movie Harley Quinn.
There were a lot of other characters in the movie who I wanted to get to know more, but their time was rushed and/or cut short because of the amount of time given to HQ. For me, that hurt the movie. Also, it seems as though the point of the movie was to introduce some of the other DC characters and building movies or shows around them, so it seems weird to not give the audience more time to bond with those characters so as to promote those other projects.
There are points at which the movie is a lot of fun, but I think it's ultimately a very forgettable movie because of what I said early: it never quite captures any of the things which the film is trying to imitate. Suicide Squad teases giving me some sort of connection with the characters, but never quite delivers. In contrast, I recently watched Black Widow, and I walked away wanting to know more about a lot of characters and parts of the MCU setting which have not yet been explored on screen.
Suicide Squad often falls short of pushing me over the edge of wanting to know more. The few exceptions to that were King Shark (who, despite being a less likable approximation of Groot mixed with Drax, was given just enough personality to make me want more); Starro (who hit enough Lovecraftian and morally gray areas that I wanted to know more; and whatever the carnivorous jelly-fish things were. After the end, I was also curious about what happened the Weasel.
Cena isn't a great actor, but he did alright at playing Peacemaker as a douchey version of Captain America. Still, do I want to watch an entire show based around that character? Maybe the show will be awesome, but nothing in this movie made me feel as though I should watch that show.
Polka Dot man somehow managed to both have a backstory which seemed like it could be interesting and be my least favorite character in the movie. Contracting an inter-dimensional virus and being a Starlab experiment is something that could have been cool to explore (and maybe the inter-dimensional thing could have had some relevance when dealing with a giant starfish from space). But, as it was, his story with his mom just lead to lame jokes and a weird club scene in which he's dirty dancing with his mom. Visually, his powers looked like he was shooting Bingo Chips. The character as presented didn't work for me.
I wanted to like Ratcatcher and parts of her story with her dad were emotional and touching. However, she also reminded me of Squirrel Girl, so that bothered me a bit. I'll accept that as a failing on my part and being a product of my own internal negative bias.
All-in-all, it's a movie that's an enjoyable 2 hours and a worthwhile Tuesday-matinee-price movie. It by far exceeded the quality of the first Suicide Squad, but a lot of the movies problems prevent it from being something memorable or something which will lift the Dc Movie Universe up from its current state. After a somewhat lackluster WW84, I think DC needed something with a little more oomph to get the overall franchise back on track as we come out of Covid lockdowns; despite being enjoyable, I do not believe this movie delivered what was needed to give the brand a jolt forward. It simply treads water.