Show me a leader who can't offer a decent apology, and I'll show you a leader who will ultimately have no followers. And to quote my mother's favorite adage, "To be a leader, you must attract followers. Otherwise, you're just taking a walk."
The true test of any apology is whether it restores trust and credibility. Apologies that are insincere, incomplete, poorly delivered, and not backed up with a change in behavior -- or better yet, a change of heart -- can damage trust and credibility far more than no apology at all.