I liked the movie but I'm not over the moon about it. Biggest positive is how they really got into Thanos to make him three-dimensional and not a ha ha ha villain. Biggest negative was the fight cause they were done in a way where the action happened too quickly and I could barely see what was happening. They were more bad Russo(Cap vs Winter Soldier highway scene) than good Russos (airport scene in Civil War).
In the case if Vision I'm thinking Adam Warlock could bring him back. Also Warlock could be a key in defeating Thanos, he somehow could be a walking gem himself. He could affect the soul gem.
Another way to bring Vision back could be via something similar to what happened in the comics. They used the brain patterns of Simon Williams/Wonder Man. In the movieverse, Simon could be a scientist charged to bring back Vision and he doesn't tell anyone and use a new energy he discovered and linking part of his essensse to do it. But what it does is change him too, gives him powers.
About Thanos, I was disappointed to see Gamora in the sort of after life instead of Death.
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Now personally I want to see Red Skull back in action. He was somehow guarding the soul gem but there has something else to this whole thing where he would want to replace what was lost by the death of so many people. Thanos is out of action, he did what he wanted, maybe you need a new threat going forward with a ultimate showdown between him and Cap.
Concerning Bucky's arm, I was hoping they would have given him Klaw's arm. It was such a simple link to make, I don't know what they did not do it.