Can we add a "death poll" to this thread with all of the potential candidates? I feel like, now that we have a second trailer, it's easier to make some bets. After seeing what we'd seen, here are my predictions:
GONERS
Hawkeye: I don't believe he's appeared in either trailer. Doesn't necessarily mean he bites hit but it could. Maybe it's just wishful thinking on my part, though. I have nothing against Renner or the character, but I also don't find him very interesting and would rather more time be devoted to more prominent characters.
Pepper Potts: There's been some speculation that she could get killed. I hope not, but I could see that happening. Paltrow doesn't seem to want to stick around the MCU forever and her appearances have become more sparse.
Iron Man: RDJ is why the Marvel Universe took off in the first place, and they owe a lot to him. He clearly enjoys the role, but he's probably also ready to move on. I feel like this film needs a major character death, and while they seem to be telegraphing that it will be Cap (with Thanos crushing him and Evans saying he's "done" after these films), I think Stark will be the big, earth shattering death.
Wong: Dr. Strange is obviously safe, but I fear that his buddy Wong might not be. His death might also give Strange more of a personal stake in the battle.
Nebula: We've seen Nebula redeem herself (somewhat), turning from villain to hero. She still has a lot of blood on her hands though, and a huge grudge against her adoptive daddy. I see Nebula sacrificing herself to defeat Thanos.
Vision: It would be a shame to see Vision die, especially since he's still a relative newbie to this universe. But like the guys on Mr. Sunday Movies said, no one seems to be clamoring for a Vision movie. That might not matter, but he just seems like a cool character on the periphery that most people aren't all that invested in. I could see him not making it out, expecially since we see his Infinity Stone getting extracted in the trailer.
MAYBE GONERS
Captain America: If I'm wrong about Stark, then Cap is a goner. I just can't see both of them making it out of this film alive. Marvel promised that this movie would have real stakes, and that means taking out one of your biggest guns. At this point, the biggest guns Marvel has are Cap, Stark and Black Panther, and you know T'Challa is safe.
Bucky: If Cap survives, I think it's possible that Bucky doesn't. I know a lot of people assume he will take up the mantle of Cap like he did in the comics, and that could very well happen. But remember, Falcon also becomes Captain America as well, and I could see that happening in the movies. If Marvel feels the Cap/Bucky bromance has run its course and Evans isn't done after all, they might feel it's time to let Bucky go. If so, expect a sacrifice that will bring all the tears.
Falcon: Conversely, Falcon has been a little underutilized in his appearances post-Winter Soldier. I don't think that they'd kill him off yet, but if the plan is to make Bucky the new Cap, I don't know where that leaves Falcon.
Drax: I think all of the Guardians will make it out of this film (except Nebula, but she's not exactly a member). But Drax isn't too bright and he also has a score to settle with Thanos, and that's not a good combination. Plus I remember there being some reports that he might give up acting to go back to fighting. I find this unlikely; he's landed some roles in prominent films in the past few years, but who knows.
Thanos: Given all the talk of how Avengers 4 is totally different movie, I could see this being the end of the road for Thanos. That would be a shame though, since we've barely scratched the surface with this character. Obviously we'll get to know him here, but it still might not feel like enough.
GONERS (in IW)
1. Vision. He's toast. But he also is the easiest to revive and that feels like a distinct possibility. Either way, he's gonna go out like a boss.
2. Nebula. She's going to intervene in Thanos' plan at a crucial moment, redeeming herself in death.
3. Loki. He's also going to try to bargain with the tesseract for the safety of the Asgardians. It's not gonna go well.
4. Nova Prime: Killing Glenn Close is maximum bang for a minor character.
5. Collector: See 'Nova Prime'.
MAYBE GONERS:
6. John C. Reilly. He's so likable and he has that cute pink family that got saved in GotG 1. Please don't make that meaningless. Get this man some plot armor!
7. Bucky. If Cap dies, Bucky will iive. But if Cap lives...
There will be some kind of cliffhanger regarding the fate of major characters between IW and A4. Which brings us to:
GONERS (in A4)
1. Tony Stark. He's gonna die and become the new A.I. that runs Avengers HQ. Also, he basically fills in the Uncle Ben role for Pete.
2. Cap. He's a man out of time, completing his arc with a noble sacrifice, reconciliation with Tony, and perhaps some kind of 'reunion' with Peggy.
SAFE (not counting Strange, Spidey, BP, Captain Marvel, Ant-Man and Wasp, who are all obviously safe for franchise reasons):
1. Hawkeye. He's cheap, doesn't need a lot of fancy effects work, and he's an original Avenger that can pop up occasionally for continuity with the new players. It's too predictable to kill Hawkeye. It's almost a running joke to keep him alive. He's safe.
2. Black Widow: Probably getting her own movie. Original female Avenger. Safe.
3. Scarlet Witch: Obviously being groomed for a bigger role in Avengers, especially since her relationship with Vision is going to be a focal point in IW.
4. Wong: Marvel is not gonna kill the only authentic asian actor in the Dr. Strange franchise. He's safe.
5. Valkyrie: Probably being groomed to become an Avenger eventually. Popular new female character with loads of potential. She's safe.
6. Pepper Potts. She's going to continue Tony's legacy, possibly pop up in the universe occasionally in the future.
7. Banner/Hulk. He'll either be cured, or perhaps become Hulk or a Hulk/Banner fusion forever and retire somewhere off-earth.
8. War Machine. His death has already been teased once, they're not gonna paralyze him just to kill him in the next movie. He's gonna retire and possibly play a back-up/cameo role in future movies. Will possibly run the September Foundation with Pepper.
9. Falcon. Probably going to be part of a partnership with Bucky after Cap gets clipped.
WHO KNOWS?
1. Korg and Miek.