In my life I've met quite a lot of members of the clergy, from a great variety of faiths and denominations, and several who call themselves non-denominational or inter-faith. Some of them have been dogmatic and narrow-minded, preaching what they believe, how they believe it, and not interested in making allowances for those who believe differently. Others, who may belong to a particular faith tradition, are amazingly open to people of all faiths.
Generally, just like with other positions and roles in society, I have found that if the person is honestly concerned about the people they are serving they perform their role in a way that adds value to the occasion. I'm not saying others can't perform valuable service at these important life events, but good clergy do a good job. And the spiritual component of life at these special times is significant. There is also something to be said for the continuity of having someone whose presence continues in your life, not just at these significant moments, but is also there for you on a daily, or at least weekly, basis.
So, in my mind, clergy do still have value in today's society. Not when they are dogmatic and judgmental, but when they genuinely seek to serve the community in spiritual matters, taking on the role and responsibility of spiritual representative on important occasions. Even if we didn't have religions any more (which certainly might be a good thing!), I believe we would still need representatives of God/Heaven in our communities, people who dedicate themselves to service in spiritual matters - and they would be the clergy.