XMA isn't a lock for $1 billion (even though I think it can reach it), whereas BvS most definitely is. There's no way BvS isn't going to be one of the top dogs of 2016...even putting personal opinions aside, that movie is about to be massive. Suicide Squad will be too, especially considering its tracking so fantastically this early on. Hell, based on the Joker's appearance alone & the buzz surrounding Leto's performance, I wouldn't be surprised if SS grosses $1 billion worldwide.
Fact of the matter is, Marvel & DC are about to make bank this year and both brands have a chance of respectively having two $1 billion dollar movies, which would equal up to four comic book movies that crossed that line in ONE year. And that's on top of Deadpool being a surprise smash hit that will have grossed between $700-$800 million worldwide on top of whatever numbers Doctor Strange does (which I'm already assuming will be exceptional).
EVERY comic book fan should be hoping & praying that this happens.