If the earlier leaked cast list is infact true, its likely going to be a retelling of the Stand Alone Complex season 1, considering they cast someone as "The Laughing Man"
which honestly doesn't have me expecting much.. part of the appeal of SAC was the combination of the Stand Alone and the Complex episodes, the complex ones slowly revealing more about the laughing man and the whole Serano Genomics cover up, while the Stand Alone episodes fleshed out the setting further and provided character development..
that can't really be done in a single film, and even if they were just going to cherry pick from the complex episodes alot would still be lost to fit it into a single film..
yes, I am aware there was 2 and a half hour OVA Film that retold the whole laughing man case, but as with everytime they make a summary film of an anime they assume you have already watched the series to completion (seriously, try to watch that Laughing Man summary film, or better yet try and watch the 3 Zeta Gundam summary films without having seen the whole series prior, your gonna be confused as heck)..
if they had just been aiming for something set in the GitS universe, but creating a unique story while keeping the characters personalities and presentation the same, it could have turned out pretty good.. but if they are infact adapting SAC, i see failure in its future..
and since im on the subject, the whole "leaked cast images" from back in August don't have me very pleased whatsoever.. they made Togusa look like some heavily aged heartless Yakuza crime boss, which goes completely against his character (hes the youngest member of Section 9, the rookie, and a family man at heart) which makes me think they are going to try and completely change Togusa's character defining traits (seriously, that image alone has me fear they will try and turn Togusa into "old veteran who goes 'god dang changing times, whats this e-mail your talkin bout?'")..
and at the same time, Ishikawa looks far to young.. although, Saito and Aramaki actually look quite accurate surprisingly..
never saw any of the franchise? certainly a classic, but there would be alot of material to cover if you want to check it out.. I would suggest starting with either the Original film (1995) and its sequel, or jump right into Season one of Stand Alone Complex.. or if your into it, I can't praise the manga enough..
the characters are great, setting is interesting and complex, the cases they deal with are often intriguing and suspenseful, and they deal with alot of serious issues (Governmental Corruption, the Dangers of societies rapidly progressing technology, Transhumanism, sixuality, with the occasional glance at religions role in a world where "human" has become so vague a term)