Q: Which is more important, character or plot?
Or, to put it a bit less obliquely, you can’t really separate the two. Plot, after all, is characters doing things, and one of the ways characters are defined is by what they do and how they do it. I don’t have a grand unified theory of character, but I do have some thoughts on the subject — as what writer does not? — and like most writers who have thoughts, I’m happy to share them.
A bit on character, action-plot style:
Moody loners and charming rogues work best as genre protagonists if they’re encountered at a cusp point in their personal life-story—or, to put it less delicately, at the point where they’re about to grow up. Nor should one forget the Three Faces of the Action Hero (sort of like the Triple Goddess, but different). Instead of the Maiden, the Mother, and the Crone, you’ve got the Kid, the Gunslinger, and the Wise Old Cowpoke, who can be seen in their full glory by considering the career of Clint Eastwood from his days as Rowdy Yates in Rawhide up to the present. They’re also conveniently displayed all three at once in the first Star Wars movie, in the Luke/Han/Ben trinity.
On matching character to problems:
You don’t necessarily want to give your characters the kind of problems they’re good at handling. Where’s the suspense in that? Give them challenges they have to rise to meet – or fail to meet – instead.
Sometimes, that can mean giving your sensitive thoughtful protagonist a problem that needs direct action to solve it. (Hey, it worked for Shakespeare, in Hamlet.) When it comes to emotional problems, the easily-bruised, show-every-dent types have practice in taking it. They know the progress of an emotional trauma in the same way that the straight-ahead types know the progress of a bullet wound, or a broken bone: Now it’s numb. Now the pain fills your entire universe. Now it’s a long, slow ache. And now it’s mostly gone, except for when you move just the wrong way to bring something down off a high shelf, or when the wind comes in from the west bringing rain.
No surprises there, in other words. So push them out of their zone of competence into unfamiliar territory, where it doesn’t matter so much what they do as that they do something, anything, right now, and watch them try to cope.
For the straight-ahead types, though, emotional trauma comes so seldom that every time is fresh and new and dreadful. (Again, it worked for Shakespeare, in Othello.) Give them problems that don’t respond well — or at all — to fisticuffs or machinegun fire or high-powered laser rifles, and see if they can cope.
Why truly good and nice characters make great role models but difficult (for the writer) protagonists:
Plot and conflict, whether of the emotional or the exterior kind, are what fiction is all about. And if you want your characters to generate plot and conflict, they need to have shadows in them to hide stuff and angular bits to catch on things.