Not a wimp -- a slacker.
There's an important difference.
Wimps are disgusting to read about in fiction. Personality disorder.
Slackers are just lazy. They are competent when they have to be.
Reading about a soldier who is broken and developed PTSD portrayed well (Hurt Locker): great.
Reading about a soldier who is a coward and refuses to kill with anxiety issues (Upham): terrible.