Many modern economists think the standard for a "good" economic theory is how well it predicts future trends. Not only are most economists terrible at making predictions, but the whole premise of economics as being about predicting things is a flawed idea.
John Rawls claimed "justice" demands governments use their power to benefit the least well off in a given society. But then he arbitrarily restricts the scope of these programs to particular nation-states. This betrays a fundamental problem with his idea of inequality.
Today's neoconservatives have found common cause with the Left in destroying those who disagree with them. In fact, this habit of denying a forum to any and all dissenters has a long tradition in the conservative movement.
Marxist G.A. Cohen is troubled by the freedom libertarians grant to property owners. But artificial limits are unnecessary when practical realities have so often intervened to limit property ownership by any one person.