And the beauty of this large teamup film is that all the character building (outside of Thanos and the Black Order) has been done in 18 other movies prior to this one, so this movie can focus on the villian and the hero interactions. SO when **** goes down, you already know who these people are, and "care" about them if something where to happen.
We all know there is going to be a body count in this movie and A4, and there are gonna be some emotional scenes when it happens as the audience has grown to know and love some of these characters over the last decade.
unrelated CU talk: It's a damn shame DC felt they had to rush to certain story points to "beat" Marvel to the the Avengers money they were already guaranteed to make. They pushed a Superman movie where Superman wasn't very Superman like, then in the next movie, they rushed to make him fight Batman, where by the end of the movie he dies... but no one really cares, because he was never a character that was fleshed out enough for anyone to care about.
DC should've been taking notes and made good character movies that led up to an event, or an awesome event that branched out into good character movies.
Now all that Avengers money they were chasing has been left on the table, and the Avengers are coming to collect it all back up.
Infinity War is going to make SO MUCH MONEY that it will likely outgross both BvS & JL, and if really hits hard, you could probably add in MoS to that combined B.O. as well. That would mean IW could eclipse $1.5b-$2b at the B.O. if everything goes as well as Marvel hopes.