That defeats the purpose of it being a wiki and is actually more limited than what we have here on the forum, where anyone can post a tutorial.
The wiki would be more for ease of access/quick reference source/source of essential information (if that makes sense.)
As for tutorial posting, consider this situation:
User X could post a tutorial on the forum about making realistic textures in Paint.net. Moderators Y and Z read it and deem it as "essential/very helpful" and post the tutorial on the wiki.
The advantage of the tutorial being on the wiki would be that other pages link to it... let's say Noob A is reading the page "Texture Hacking 101" and is directed to the new tutorial.
As for the wiki lacking traffic, you could make a rule that says new hacks/modders should consult the wiki before posting a help question on the forum, only posting a question if they can't find the answer on the wiki.