I didn't say it wasn't a big blockbuster. I'm saying that Batman and Superman are a big blockbuster, period. No need for firsts, seconds, thirds. Those two on screen together should be like printing money, no matter how many times we've seen it before.
with that in mind, i don't see a need to have a "solo" movie of the two, and then a JL movie, when you can lead with JL, follow up with a few of the lesser knowns, hopefully getting a boost of JL. Then you do you B&S movie. It'd still be big, it'll still be an Event. but I don't think FIRST is necessary for it to be either of those.