It was written in 6 weeks. Characters are badly written, some of them are pointless, the whole plot makes zero sense, Joker appears in the movie just a bit more than in trailers, Leto's Joker is probably the worst Joker ('damaged' tattoo....Jesus Christ), music is badly used, villain is hilariously bad (so is Cara's acting), then they made an extended version that didn't add anything to the movie....I could go on and on and on...
If you want to watch good Suicide Squad movie, I recommend "Batman: Assault on Arkham" (http://www.imdb.com/title/tt3139086/)
They tried to do "assemble cast" movie like Avengers and most probably Guardians of the Galaxy but they failed miserably.