It might seem like a pessimistic way to spin the upcoming ensemble, but there's a certain element of the Infinity War hype dedicated solely to the idea that we're going to see beloved characters killed off. And if you don't believe that that's a big deal for fans of ANY major fandom, go and look up any franchise and Predicting Who Dies on Google - it's almost obsessive the lengths we go to as fans to convince ourselves that directors are always one step away from straight up murder.
Even while loving the characters, we want to see film-makers have the audacity and the bravery to kill major players off and Infinity War looks like the perfect opportunity to swing the axe. Not only are several veterans coming to the end of their contracts (or more importantly their real value to the franchise in some cases) but Marvel already have properties they can rely on to become the new A-list MCU properties.
But, no matter how many times it's promised or we're warned, there's no way Infinity War will kill off the number of characters everyone is expecting. Looking at the long list of characters, you could feasibly see more than10 major to supporting characters killed (ignoring the villains) including Cap, Iron Man, Hawkeye, Bucky, Vision, War Machine, Falcon, Bruce Banner, Scarlet Witch, Black Widow, and Nick Fury without it really impacting plans for Phase 4. And really, that's what Marvel SHOULD be doing.
But they won't.
This is a DISNEY property under all of the other moving parts. It's also part of the MCU that has so far been shy with its kill-count and even more shy with any flirtations with real darkness. And it's worth repeating that Kevin Feige did say tell fans at an Age Of Ultron Q&A that expecting a dark turn is foolish, according to one Redditor in attendance:
"There is no dark turn in the MCU. He says every year fans come up to him and ask him if this movie is when the MCU goes "dark" or takes a "dark" turn. He said while the trailers may seem ominous or have a sense of impending doom, the movies do not have that feel, and will not. He said he "Hoped people would catch on by now" - there will be no giant dark turns in the MCU where it then continues to head in that direction. The humor is in the DNA of the movies, there are no plans to change that."
How could they reconcile that much death with "no dark turn" - it's just not happening. So, while there may be some fatalities, it's not going to be the bloodbath some are expecting.