katsklaw, if people want to use vhost characters that aren't rfc compliant, thats their problem, many characters will not break rfc, anope's hostserv doesn't allow many vhosts that are rfc compliant, for example, all vhosts are required to have at least 1 dot in the host side; first of all, .'s should not be required, most if not all ircd's could care less if there is a dot, but not only that, the : character is a perfectly valid (like for ipv6) and its not even allowed in a vhost, that makes no sense.
have you ever seen the freenode ircd ? it has ='s in the username field, and /'s in the host field (like lu_zero!n=lu_zero@gentoo/developer/lu-zero), this doesn't break rfc or any clients. Just because you (one person) doesn't see a reason for it, doesn't mean that others don't. i would also like to see this feature.
Anyone who breaks things by using such a feature (like adding ! or @ to the char list) its their problem, not yours. you could even put a warning, use at your own risk in the example config file.