If Affleck actually does want out unless Wonder Woman and Justice League are very well received I do think they have to pull some Flashpoint-ish stunt.
I also like how people are ignoring the whole contracts issue. Most of these people are under multi-film deals and most haven't even released their first film in that deal yet.
Im not saying dump the actors exactly.
Aquaman - he will just be meh at worst imo and inoffensive.
Wonder Woman - people generally liked her in BvS she would need to tank WW and JL on her own to be unsalvageable.
Superman -easily fixed
Flash - actor will be fine, suit can be fixed
Cyborg - redesign, keep the actor but change the solo to Teen Titans if bad
Batman -is fine unless Ben actually wants out
Lex- .... I have no clue
Joker- keep the actor just redesign from the ground up, write him differently, reel him in a bit.
God forbid they try to give Superman an actual story arc in the universe.
As for Lex, it's easy. Lex gets out and prison/Arkham has changed him. He comes out cold and calculating and leaves the nonsense behind. We already saw glimpses of it with him and Superman on the roof.
Joker.. Joker is just screwed. However, if someone could tell Leto to stop playing him like he's nodding out on heroin and gave him better material and I could probably live with it.
Problem is Superman was just a bit bland initially but legitimately disliked in BvS,
With him returning in Justice League which still has Snyder directing I just don't have faith he can do it.
Lex yeah I agree but its going to be a lot of effort winning people back imo.