The ability to do a quick preview scan of a site - just spider links and mark discovered broken links
This coupled with the ability to exclude links to follow could help ensure full scans run successful on larger sites without wasting so much time. Basically spider all site internal links out to external sites one page . This information could also be useful for link audits as well.
Unless I misunderstand the request, you could do this by simply only enabling the sfp_spider, sfp_dns and sfp__stor_db plug-ins, which will spider the target, and then you would look at the HTTP Status Code elements to see the cases of 404, etc.