I just saw it, and honestly thought it was pretty damn good.
Despite, IMO, massive plotting issues.
The actors pushed this just above pretty damn good, IMO.
But yeah, how do you screw up a concept like this? The Squad was cleaning up Waller's mess, Slipnot's fate was rather predictable even if you hadn't read the comics, Katana was pretty pointless, Waller was far too ruthless (not words I ever expected to type), Joker's appearance was too random, the list goes on