I parsed your OP differently; I understood your OP to be suggesting that there were no exceptions to the priest-penitent privilege, and wild exceptions to the attorney-client privilege (including an exception to the privilege requiring a lawyer to report any planned crime, which would be an absolutely ludicrous exception that would gut the entire privilege).
I will note, however, that even this much broader statement isn’t accurate. First, many non-US jurisdictions have only very limited priest-penitent privileges (UK and Australian dopers, please chime in). Second, most US jurisdictions do not hold the priest-penitent privilege to be absolute (see, e.g., rules that priests are mandatory reporters for child abuse).
What I took exception to in the OP was, specifically, the following:
First, and as noted above, the priest does not have absolute privilege.
But, second, and more importantly, I am not aware of a single US jurisdiction in which a lawyer or doctor is required to report every “future crime” to the authorities. There are some jurisdictions that require a report of a future crime that is reasonably certain to cause death or grievous bodily injury, but that’s a pretty narrow exception. And some jurisdictions don’t even have that exception. See, for example, California, where attorneys may, but are not required to, report a crime that they reasonably believe will be committed that will cause death or grievous bodily harm.
So in some senses, the exceptions to attorney-client privilege are narrower (I’m ignoring SOX). Assume a client comes to my office, and as part of our discussion, he asks me for advice on how to molest kids. I give him the advice (don’t do it, it’s illegal, etc.), and he says, well, I hear you, but I’m going home and molesting my kid anyway. I cannot disclose that admission.
Assume my client leaves my office, stops by the church, confesses his sins, and then tells the priest, well, I hear you, but I’m going home and molesting my kid anyway. The priest must (not may, but must) report that to the authorities.
In that instance, then, the attorney-client privilege provides more protection from disclosure than the priest-penitent privilege.
With that, sorry for the hijack; it just bothers me when inaccurate statements of the law are used as the basis for an otherwise interesting discussion.