As Adblock knows how many ads it has blocked from a site - perhaps an option to limit the number of ads per page would be more workable. e.g. The user could limit adblock to show 1 ad only - and block all other ads (or even block all ads for pages which have more than 1 ad). This may force developers to at least stop having pages filled with ads.
I foresee a situation with the proposed solution that ALL developers claim to be squeekly clean on non-intrusive ads (even when they are not), and users just stop believing them - and revert back to blocking all.
Personally (business oportunity here) I would like to use a search engine which (using some inteligence from AdBlock) displays how many ads are in the linked page with the search results, with an option to sort the results by number of ads - any offers?