Marked defect, but it's a little bit of defect and a little bit of enhancement.
Patch contains corrections for modern Gentoo stable (with the exception of a couple of specific packages from ~amd64/~x86).
Also contains enhancements for setting SUEXEC user and group from config, as well as ProFTPD min uid and gid. Also contains support for mod_fcgid, which works, but someone might like to review it for security/sanity. I also believe that mod_fastcgi is non-working with these configs, but I have no inclination to test it at this time.
The Gentoo wiki article is also sorely in need of an update, but these patches should at least make everything work out of the box. The only additional user step once required packages are installed, and ispcp-setup is complete is to install the postfix smtpd chroot, for which a script is available in the postfix package. Maybe chroot should be disabled in the default config.