Yeah, I think WB has been on the reactionary side in how they plan for movies. If there's enough positive reaction toward Superman in this movie, it'd be hard for them to ignore.
I was just thinking, MoS came out in 2013, and if 2021 is the earliest we get an MoS sequel, that's going to be a fair amount of time between movies. I wonder how much longer Henry Cavill is going to want to keep doing this. Hope he doesn't lose interest before they can make a couple more solo films.