Am I missing something here?
One of the biggest bugbears of editors and often repeated is the sheer quantity of spam in the site submission / site suggestion queue that prevents them from constructively finding and adding new sites from the queues.
In which case you need to reduce the spam/noise/"toxic sludge" without impeding the worthy submissions.
As an outsider looking in….
1) Add a “captcha” to the submission page (Human submitters for Human reviewers)
2) Send out an email to the submitter requiring confirmation
3) Allow submitters to have a unique username or even better (more coding) a submitters account.
This should instantly cause the volume of unsuitable sites submitted to fall dramatically. It will also allow you to profile the submitters.
All easily coded and all totally automated.
Result - Editors task is easier and genuine gems get listed faster.
It seems too obvious and too simple? What am I missing?