My suggestion for controlling spam on that board will be for moderators to lock any thread exceeding 50 pages, no matter how interesting anyone thinks the discussions going on there is. Secondly, campaigns should reduce their weekly post count requirement on that board to just five posts instead of 10. That way, participants won't hastily populate those threads with unconstructive posts and make them redundant.
I am a football lover, so i will use the footballing threads in the gambling discussion section as an example, most of those threads are peculiar to a particular football league and the Champions league all season long, and a season lasts from August till May, that is about 10 months span, imagine if mods have to lock each thread that gets to its 50th page, mind you that it will get there (50 pages) pretty quickly as football discussions go on endlessly there, if that happens we would prolly have new topics created, locked and another created again in the same day, everyday. That will make matters worse, and i would not want that cause i am active in that section.
As for signature campaigns, we can't dictate what their requirements should be, there are quite a lot of users making more than 20+ constructive posts in the gambling discussion section, it is very easy to do if you love football or the dedicated thread of the sport you are commenting in. There will always be spammers, just as there are in every section, so the 'reporting' method should still suffice.