I sit firmly in the no camp on the basis of necessity, precedence and existing structure.

Worldbuilding can already be done with the existing structure perfectly fine.
> The Char tab can become the lore center for a roleplay. Use Post 0 as the index, if your lore spans multiple posts. So long as things are properly linked together, the Char tab is an infinite means of storing lore. It's simply up to you to make it work, and I don't think it's difficult to make a sustainable structure for it.
> The Character Sheets forum [i]already[/i] contains worldbuilding. The site staff are liberal in what they allow to go into each section. There could be a little text latched onto the section to make it more expansive, but like the current roleplay sections, it is not strictly enforced. Just as the casual forum contains roleplays that fail to meet all of the minimum requirements, or contains many threads that would easily fit Advanced requirements, people can stretch the Character Sheets forum a little without causing issues and clutter.
--> The Character Sheets forum as it is was not designed for ease of navigation. There is no index, only a flat list for people who are curious to browse. Worldbuilding and character building are very similar themes, thus, it is not offputting to scroll past both of them. At any rate, people who use the Character Sheets forum use it by linking to their specific thread within that forum on their signature or whatever.
> Threads on RPG aren't even designed for worldbuilding, which brings up the point - why even have the worldbuilding on site if you can use a Wiki, something specifically designed for worldbuilding? Adding a new forum will not add a new system for thread creation, ie, a thread designed to operate as a mini wiki. It would probably have the same sort of threads as the other forums down here, which means you might as well just use the above suggestions if a line of posts with decent formatting and hiders is just fine.
> The Test forum has been used for storage before, and as long as people aren't excessive about putting it to use, it can be used for storage again.
> The Gallery is also a fairly fitting forum for this purpose. In fact, it may even be superior to the Character Sheets forum - 
[quote]Come share your own art and [b]literary work[/b]! (Includes shops & requests)[/quote]
Worldbuilding sounds like a valid form of literary work to share. I made the case for the Character Sheets forum, but really, if you want specific text to cater to it, the Gallery does it best.

The Guild's structure is partially appealing to me because it does not suffer from clutter, unlike other roleplay forums or even our own discord. Is it perfect? No. Does it work just fine, and has it worked just fine for quite a while? Yes. Add a "World-Building" forum, and why not turn around to add an "Anime" forum and all sorts of other forums for topics relative to people's interests? You can stretch the Anime forum to be regarding Anime lore and its use in roleplaying contexts. I would consider it an absurd addition. Yet, I believe adding a forum for this niche purpose would give precedence to add more forums on looser standards, which opens the door to valid requests for every type of forum that you can justify with a couple paragraphs and maybe even a half dozen people saying "yes".

Adding such a forum, in my book, is entirely unnecessary and simply not something I would consider a priority. I'd look at the Expanding Horizons forum and adding new blood to the Contests forum long before something like this concept.

Apologies for the word vomit.