There are a few problems.

First, OpenBSD's update process is limited. While it's improving, and oBSD wasn't vulnerable to this potential exploit, my experience has been that of the three major options (Debian/apt, RedHat/rpm, oBSD), the ease-of-maintenance continuum flows left to right.

Second, OpenBSD lacks SMP support. Uniprocessor only. That's a nonstarter for several of our systems. As an appliance, it's acceptable. As a server, it shows clear failings.

Third, even placing oBSD as a bastion system in front of your servers, you're open to exploits in CGIs or other server-side software, behind the firewall. Security is a process, not a product.

I'm happy with the fact that I am able to update my Debian systems within 24 hours of this alert with no issues. Red Hat I'll have to wrestle with over the course of the day, and OpenBSD I'm glad I don't have to mess with. Given a choice of "secure by default" and "very narrow vulnerability window", I've come to prefer the latter, though a sane-by-default configuration also helps.