Old Gunn has been playing his cards close with the whole 'returning cast' 'new cast' reboot, quasi reboot.. there were some parts of SS I loved, I thought Viola Davis nailed her character, Margot Robbie obviously is a better Harley Quinn than Harley Quinn actually is Harley Quinn, if that makes sense.
I thought the guy playing Flagg, was horrible. Diablo, Killer Croc. I wasn't huge on Captain Boomerang but I definitely got a scumbag feeling from him so that is good.
The plot obviously sucked, Gunn can totally fix that. With the characters he has coming back and the rumoured cast I am sure SS2 will be a good movie. As long as Leto is done as the Joker