I saw the movie Watership Down for the first time a few months ago (right before Easter, which made all those cards with bunnies on them suddenly look very morbid). For anyone not familiar with the story, it's about a group of rabbits led by the brothers Hazel and Fiver who leave their old warren to start a new one and encounter several predators and enemies along the way. It's one of the darkest and most highly acclaimed children's movies ever made, and while I did love it, there's one nitpick about it that bugs me every time I watch it.
The rabbit Hazel is treated as the main protagonist in the story. Everyone hails his leadership skills throughout the film, he orchestrates the plan to defeat the villains during the climax, and he gets the big heroic sendoff in the final scene. What bugs me is that I don't quite understand why he's the main protagonist. He's not a particularly interesting character, and while he does have the main conflict to deal with, he doesn't really have a personal story arc. His brother Fiver, on the other hand, is a runt who gets pushed around by the rabbits in the old warren and whose connections to the spirit world help him to see the future and point the group of deserters towards their new home. Fiver is the underdog with a unique ability who incites and drives the story. He's a much more compelling and pivotal character, so why is it Hazel who gets the ultimate spotlight?
This isn't the only case of a sidekick being more interesting than the designated protagonist in a story. Eli Wallach's character Tuco Ramirez in The Good, the Bad, and the Ugly is much more colorful and engaging than Clint Eastwood's character Blondie, yet it's Blondie who always gets the last laugh as the hero with a plan up his sleeve. There's also Dennis Dun's Wang Chi in Big Trouble in Little China, who follows the lead of Kurt Russell's Jack Burton despite having more at stake. Heck, even James Bond is pretty one-dimensional compared to most of the assistants, contacts, and love interests that he's had over the years. It's odd from a writer's viewpoint to see so many dynamic figures forced to be second bananas to stiffer and blander ones, so why do so many authors and screenwriters do it?
The most likely reason is because characters like Hazel, Blondie, Jack Burton, and James Bond are more serviceable to audiences than their sidekicks are. They have less distinct personalities, so it's easier for us to project ourselves onto them and pretend that we're the ones living their lives. This type of character is often referred to as a Blank Slate, and while they're still commonly used in storytelling for the above mentioned reason, we do see a shift in their role as the protagonist every now and then.
Just look at the Pirates of the Caribbean movies. At first they seem to present another case of a Blank Slate protagonist who's going to have a dynamic sidekick, but Will Turner quickly gets demoted to a helper after he meets Captain Jack Sparrow. The two spend the rest of the original Pirates trilogy pretty much competing with each other to be the main protagonist, then Will drops out of the series altogether in the fourth film and Jack has the stage to himself. It's almost like the screenwriters were afraid to make Jack the hero at first and gave him a more standard counterpart to be safe, then when they saw how popular he was with audiences, they took off his Will Turner training wheels and edged him into the leading role. Sources say that Will is supposed to return in the fifth Pirates film, though it's unclear whether or not Jack will have the same relationship with him as before.
Another supporting character who famously became the protagonist in his film series is Peter Sellers's Inspector Clouseau, who first appeared in the 1963 crime comedy The Pink Panther. In that film, the protagonist is a jewel thief named Sir Charles Lytton who attempts to steal a famous diamond while Clouseau is simply a detective who investigates its disappearance. Clouseau was technically an antagonist in that movie, but his bumbling persona was so memorable that he took over as the hero in the next five installments of the series, though not always played by the same actor. That's not even counting the two reboot films from 2006 and 2009 that featured Clouseau in the lead with no mention of Lytton. Once again though, this more engaging character had to be broken in with training wheels before he was allowed to be the protagonist.
Judging from these examples, audiences seem to like having more memorable main characters. The recent criticism of Twilight's Bella Swan and poor performance of Hardcore Henry, an action film shot entirely in the first-person point-of-view, also seem to suggest that a lot of readers and filmgoers want more than a Blank Slate to project themselves onto. So again, why are so many three-dimensional characters relegated to sidekicks and supports for one-dimensional ones?
Whatever the case, it's still nice to see a second banana grow ripe and get picked every once in a while -- or a second carrot, if Watership Down ever gets any sequels.