Early Avengers: Infinity War concept art reveals that Thor's epic showdown with Thanos toward the end of the movie could have included other Avengers. Instead of literally flying solo, Thor would have had plenty of backup to help take down the Mad Titan before his cataclysmic finger snap.
By the end of Avengers: Infinity War, hope is all but lost when Thor finally shows up in a true deus ex machina moment. Wielding the mighty Stormbreaker, Thor singlehandedly takes on Thanos moments before he's able to follow through on his plan to wipe out half the universe. Unfortunately, Thor's grand entrance is lost on a technicality, and Thanos succeeds after all. However, things might have played out very differently had directors Joe and Anthony Russo stuck with early concept art for the film that lent some helping hands to Thor's final one-on-one interaction with Thanos.
As part of Marvel's Avengers: Infinity War - The Art of the Movie (via: Comic Book) comes a look at an earlier version of Thor and Thanos' final face-off in Wakanda. Similar to the scene on Titan, in which Iron Man, Spider-Man, Star-Lord, Drax, Doctor Strange, and Mantis team up in order to fight him together, this scenario appears to take place directly after Thor stabs Thanos with Stormbreaker. He's evidently less injured and is able to fend off Thor, Captain America, Black Widow, and Hulk (who is fully transformed from Bruce Banner in this early concept art).
While this scene clearly showcases a much different direction that the finale for Avengers: Infinity War might have taken, the most interesting takeaway has less to do with the entire group of characters involved than it does Hulk himself. As intriguing as it might have been to see these characters essentially recreate the scene on Titan in which members of the Avengers and the Guardians of the Galaxy attempt to remove Thanos' Infinity Gauntlet, having Bruce transform into the Hulk would have been a major game-changer. Whether it would have actually changed anything, however, is a different story.
Now, looking to the future, it will be exciting to see heroes who were separated from each other in Avengers: Infinity War reunite (or even meet for the first time) in Avengers 4. Marvel Studios will be wrapping up their 22-film arc, so audiences will no doubt bear witness to some spectacular narratively-appropriate fan service, including a satisfying payoff to Bruce's inability to transform into the Hulk, Steve Rogers and Tony Stark reuniting, and certain characters who are literally dust in the wind making their inevitable comeback.
Source: Marvel's Avengers: Infinity War - The Art of the Movie (via Comic Book)