I would start with post pumping; it is both too vague where needed and too detailed where problems don't really occur. When coached on post pumping the general take away always seems to only be don't post "I agree". As you can see in the following link http://www.callofdutyzombies.com/forum/index.php/topic/158976-non-response-responses/ . However the real problem is with posts like this:
These are the posts that add no substance whatsoever to the forum. However they never seem to be addressed. I think the reasoning is that post pumping seems to be in a grey area.
Duplicate posts seem to be on the rise. Folks starting up new threads daily for information that we have already worked on months ago. As stated in the CoC it is on the members to know the previously posted content. Is this no longer the standard?
Signatures- If you look at my signature below it is well above the maximum size. However compared to most it is quite modest. I understand at one time there was an issue with people adding 14 huge pictures to their signatures and it taking quite some time to scroll through the page. So the current state is that no one seems to follow this rule so I would recommend amending it, removing it, or enforcing it. For a CoC we shouldn't pick and choose which rules to follow, ya feel me?
As far as what needs added, you tell me. What are your day-to-day issue that you can do nothing about because to rules have been set to prevent it?