The suggestion is very simple.
The maker of a thread can choose members or a member who can edit his thread. So that he isn't the only normal member that can edit the thread.
This would be really useful in the Small Clans section. Sometimes a non-leader of the clan makes the thread, because off that, the leader of the clan can't edit the OP post.
Or this could be usefull when two or more modders colaborate on a mod pack.