All your criticisms are perfectly valid of course even if I disagree but I have to wonder about the "providing team member introductions all within the same movie" bit. I mean before Phase I of the MCU was this ever really a problem? Did anyone complain after seeing Star Wars that we should have gotten solo Han, Luke, Leia, Ben, Chewie, and Droids movies?
Or a solo origin film for all nine members of the LOTR Fellowship? Or all the sports movies that center around a team of players, war movies about a platoon or squad, Seven Samurai, Dirty Dozen, and countless others.
Even with regard to superheroes Singer's X-Men seemed to do a pretty good job of introducing everybody in one movie. And like you said the Trinity at least got their intros in the prior two films. For me it just comes down to does it *feel* rushed or just a natural organic introduction with all the necessary info to make me care about any given character? And while I do think that having Batman and Supes face off so soon in the prior movie did seem rushed, same with killing off the latter, I didn't actually feel that way with the ZSJL intros, especially since the run time was basically two entire movies anyway.
I'm waiting to get the new IMAX BvS before I binge all three but I'm even wondering how rushed the BvS fight and Supes' death will feel now that I have the grander tapestry in mind. I kind of suspect that judging the whole thing on it's own finished merits instead of by "how the MCU did it" I'll find that it plays much better going forward.
