SPOILER WARNING: This article is all about the ending of Avengers: Infinity War. This is seriously dangerous water. Come back after seeing the movie! Why did you even click this if you haven't watched yet?!
Avengers: Infinity War promised to be a massive spectacle filled with action, a threatening villain, a host of lovable characters, death, and heartbreak. Indeed, Infinity War has all of these things, but the latter two have proven to be somewhat subjective amongst viewers. People expected Infinity War to feature character deaths, but I doubt many expected Marvel to wipe out half the cast. At the end of the film, Thanos actually wins and succeeds in his mission to wipe out half of the universe, taking several fan-favorite characters out of the picture.
However, while some have openly admitted to weeping right there in the theater, others have voiced their criticism over an ending that they think lacks teeth. A common refrain from fans at CinemaBlend has been: "Black Panther and Spider-Man aren't gone for good; they each have sequels coming out. Why should I care when all these characters are coming back anyway?" That is not an entirely invalid criticism, but it's more reflective of modern filmmaking and our constant awareness of it than it is the actual movie.
Of course the ending to Infinity War matters. It actually matters quite a lot because Captain America doesn't know that Bucky needs to come back (hopefully to take over his mantle) because Chris Evans' contract is up. All he knows is that his best friend is dead. It matters because Tony Stark thinks he failed his mentee and doesn't know if he'll be heading back to Earth to find a welcoming Pepper Potts or an empty home. It matters because Peter Quill didn't get to mourn the love of his life. It matters because the likes of Rocket and James Rhodes are going to feel the losses of their friends.
In short, I strongly believe that the people who say that these deaths don't matter are forgetting to divorce their knowledge as the viewer from that of the characters. Many of us are fans of the movie business and Marvel in general, people who like to follow the trades. There was no doubt hundreds of Marvel fans who walked into the theater thinking that Black Panther had the greatest armor in Avengers: Infinity War of all the characters: a billion dollar franchise. I certainly did, which only fueled my pure shock all the more when T'Challa turned to dust right in front of Okoye's eyes.
You could spin that around and say, "OK, well, Marvel killed Black Panther, the most popular new hero, so everyone has to be coming back." Yeah, no duh. Marvel isn't just going to kill all of its new heroes and franchises just for the hell of it. People have basically universally agreed that many of these characters are coming back, and the Internet is already debating how they will be brought back. The how of this scenario is definitely fun to think about, but maybe the more important question is this: How are the characters who are left going to deal with the loss of their friends? Because that's where the stakes really kick in, and we will see the emotional impact of how these deaths have shaken the MCU.
The heroes have no idea there's an Avengers 4. At that moment, they truly think that all of their friends are dead for good and that they've failed half of the universe. You can tell that it has clearly shaken all of them. At the end of Avengers: Infinity War, Steve Rogers can do nothing but crumble to his knees; Black Widow looks like she's going to throw up; not to mention poor Tony Stark, who held a dying Peter Parker in his arms as he evaporated into dust in the scene's most effective death.
This is devastating to these characters, but also to the fans. Even though as a viewer who knows that this is not "The End," that doesn't mean the deaths aren't effective in the moment. I can't speak for everyone, but I know that for myself -- a person who is constantly on the pulse of movie news -- this scene surprised the hell out of me. I walked out of the theater knowing these characters would be back, but I still couldn't believe Infinity War it ended the way it did. Again, this is a specific example of what worked for me.
One argument for why the ending falls flat for some is that the movie itself isn't standalone and that it doesn't do much in its own runtime to make these final deaths really land. For example, Bucky has maybe five lines in the entire movie but a fair amount of weight is put on his "dusting." The movie is depending on the fans already knowing the characters and their relationships so that it doesn't have to do as much legwork. But...is there really anything wrong with that? This is the 19th film in a connected franchise. If you don't have enough feelings for these characters at this point, there's little that a movie as crowded as Infinity War can do to change that.
There's also a wider critique going on about how the fact that these characters having sequels diminishes any sort of stakes or lasting consequence, which is a long-running criticism of the MCU. I don't disagree with this entirely, but, again, the movie can't help that you know there's a sequel. It's unfair to judge a film based on knowledge of the larger movie-making business, much like how it's unfair to blame the studio for being a business and promoting its future projects.
Look at it this way: When you watch an older movie for the first time, you're likely not thinking of all the news that was associated with it when it was made. You're just watching a movie. Fifty years from now, people will be doing the same thing to Infinity War and those people likely won't remember, know, or care about the original fan theories, what the trailers were like, or #Where'sHawkeye. All of that is extra noise that perhaps gets in the way of the enjoyment of the film in the present.
This is not to say that any criticism against Infinity War is wrong. The movie has almost no characters arcs, and it moves from one set piece to the next perhaps a bit too fast. It's OK to critique and still like the hell out of the movie; I just think people are being too flippant about the ending. Yes, these characters will return for sequels, but that doesn't change the fact that it's devastating in the moment. To cite sequels as a criticism is not a judgment on the movie -- it's a judgment on the business model.