It's not terrible, but it hasn't caught on, at least not at the national level. I suspect it's just a sore Lakers fan thing.
The problem is I don't think this insulting name really gets at the root of the problem.Howard is terribly wishy-washy. He wants to simultaneously be liked by everyone, be the best person on his team, and to play for a contender, and over the last few years he hasn't made it clear which of those is his priority. His problem is indecisiveness and a bit of immaturity, not cowardice.
For once, however, I think Howard has made the correct basketball decision. If he wants to win a championship in the near future, Houston is a much better option than the Lakers. As a large market team with shitloads of money, the Lakers can manage to retool in a few years, but Howard is very likely just starting the last half of his prime. He wants to win now, not in a few years. With James Harden and quality role players in Houston, Howard has a chance to win now.