Oh Meryl. . . people both love and hate her. I love her. Okay, maybe the very first time I saw the show, she wasn't my favorite in the first few episodes, but that's because I didn't understand her or her role. I think I do now. Out of all the Trigun characters, Meryl has the biggest contrast between what she feels and what she says, and I find that interesting. She also fulfills a pretty important role in the story.
I think the fact that Meryl was assigned to hunt down the most dangerous man on the planet says a lot about her capabilities and work ethic. Her tightly wound personality provides more opportunities for Vash to be humorous. She provides a nice foil for him. And one of the most important aspects of her as a character is that she embodies (almost) everyone's experience with Vash the Stampede. So many minor characters go through theses same stages.
For Writers: You might want to consider creating a character that embodies the average guy or girl (generally speaking). Sherlock had John Watson. John Watson embodies the average guy and as such, he helps us as an audience keep up and connect with the psychopath genius. Not every story needs an "every man" character, but if you're audience isn't connecting with your story or characters, consider creating one.
