[Inspired by the upcoming debate on the topic, which features our esteemed Executive Editor arguing the other way.]
My answer, of course, is "no." It's obvious if you compare trends in wimpiness and trends in religious belief that the decline of Christianity has turned people into wimps. Nietzsche is big among left-wing academics. Wimpiness is big among left-wing academics. It's wimps who have superman fantasies. People, you should connect the dots!
A wimp is someone who can't stand his ground because he thinks he's nothing and has nowhere to stand. You won't be a wimp if you know what you are and what you have to do. That means that a Christian can't be a wimp, not without abandoning Christianity.
In contrast, nihilists and relativists can be wimps or psychopaths but not much else. They can assert themselves simply as such, as if they were somehow a law for the universe, or assert nothing at all and give in to whatever is pushing them at the moment. Or maybe they can hunker down and do nothing. Or act randomly, by Brownian motion as it were. Why make those the choices by choosing nihilism or relativism?
But what about "turn the other cheek"? If you want to understand startling injunctions, you look at how the pros handle them. Was Jesus a wimp? Did he turn the apostles into wimps? Or how about Thomas Aquinas, Saint Francis, Saint Ignatius, or Saint Joan? Could any saint possibly be a wimp?
If you go a bit lower in the spiritual pecking order, it must mean something that neither Chaucer or Boccaccio or any other writer from the Christian centuries bothered with the Wimp as a human type. Their people had flaws, but wimpiness wasn't one of them.
At bottom, I think, "turning the other cheek" means abandoning contentiousness, acting rather than reacting, and accepting a standard that you don't think you'll grasp or achieve perfectly and doesn't make you the center of everything. The injunction strikes me as a way of shocking people into stepping back and looking at what they're doing from a less small-minded point of view. Maybe it's just me, but I don't see what's wimpy about that.