We talked about this already in the matrix, but I'm proposing it here in case there are any other ideas.
To keep empty forums off of the increasingly immense forums lists, forums would only make it onto the lists once 10 submissions have been made.
Submissions to brand new forums would still show up in /all, but wouldn't be added to the /Forums page until they are proven to be viable.
It would give incentive to founders to build their forums a bit before they debut them. So many forums are made and abandoned, never getting even a single post. It clutters up the site and encourages forum squatting.
EDIT: Changed 'list' to 'lists'.