I don't think SJ is really geared for that. Strangely enough, despite using terminology for comic strips and making a big deal of the upload date and such, as if for strips, SJ really seems better for long-form comics, where individual page tags aren't important in most cases.
But if you really want your comic to be searchable, try Oh No Robot
, which is a webcomic search engine that lets you enter the script for each page and let users search by that. Obviously it only works but comics that are in their database, but it works as a nice opt-in version of a tag-based search engine for individual pages. Face it, most people are going to ignore the tag section if we get one, so it's opt-in anyway. Why not unify it with a larger database anyway? Those who care can do their searching, Dan/Admin doesn't have to do anything, and those who don't care can just keep on doing what they're doing.