Last we knew, some sort of UGC is part of the longterm plan, but probably not implemented in the way you're imagining. From Aradune:
"Well, ideally you only provide developer style tools to a very small percentage of your player base. I think it's safe to say that there should be at least 1% of your playerbase who has the skill and integrity to be equipped with a version of your in-house developer tool(s). But even 1% is huge -- if you have 100,000 players, that means you suddenly, in theory, have 1000 additional game designers at your disposal. This could truly change the face of your game, the quality and quantity of content generation could skyrocket, and truly dynamic worlds could suddenly be within your grasp. Likewise, since it's only 1%, you didn't necessarily break that fourth wall for the other 99%.
As for why I haven't written much about our long term plans and how they involve UGC, I guess the reason is threefold:
1. Truly harnessing that 1% is no easy endeavor -- creating that tool you would then distribute to non-employees is no simple task. Lots of planning and restrictions need to be incorporated. Obviously, for example, you need to have a solid item point pool system in place before you allowed your 1% to create items. And if you didn’t, the consequences could be quite nasty (Fiery Avengers dropping from mobs in low level dungeons and the creation of seriously broken and imbalanced content).
2. The Sekret Sauce factor. While I prefer to be as open and accessible as possible, I don't know if we're quite ready to release our UGC plans to the public yet. Incredible potential lies within the realm of UGC, but unless you're creating a true sandbox there's still a game whose integrity must be guarded. I think we should probably be quite a bit farther along and much closer to reaching the Grand Vision before we get too open Kimono.
3. You don't want to distract your playerbase with ideas and plans that, at least on the surface, could be interpreted as a significant departure from people's understanding of Pantheon: The Game. I've found it very easy to unintentionally panic our community by throwing new ideas for game mechanics and features out there without very carefully establishing and explaining the context and how it does indeed mesh with the Vision. I do talk about the Grand Vision on occasion and I usually do so because I want our community to know that we're in this for the long haul and that we have some great places we want to take Pantheon after release. I want them to know we are both focused on making a great game now but also have exciting long term plans. So I try to limit the details in order to avoid creating chaos and concern.
Likewise, you also don't want to needlessly panic your development team, stressing to them on one hand the importance of establishing a solid foundation upon which to build new ideas and differentiators and then potentially on the other hand derailing the focus necessary to move an MMO's development forward, slowly but surely, by talking too much about long term, post launch, and potentially risky plans that would require both a significant effort and also some significant changes.
Mostly, though, it's probably the sekret sauce factor that I have to admit restrains me. I think the first MMO that successfully and significantly harnesses UGC is going to change the face of MMOs forever -- it really could be and should be a paradigm shift. And whoever gets there first not only likely reaps some real commercial rewards but also will find themselves in a position to shape the emergence of real UGC for everyone."
(Source: https://www.pantheonmmo.com/content/forums/topic/3898/did-he-say-quot-user-generated-content-quot ;)
Note: that image is from the Kickstarter, and like pretty much everything from the Kickstarter, the details should not be assumed to still be true. Personally though imo, if it is a completely separate server, if you don't want to play on it, it really has no effect on you or the rest of the game. They wouldn't just stop GMing and improving the "base game."
I always thought UGC was something that happened after publishers would ordinarily have dropped support for a product, so they pass it along to the fans. A bit like Everquest and Project 1999, only more official.
Of course, if that possibility were 'baked in' to begin with, you could harness the concept a bit earlier and have UGC when the official servers are still running, but I would be VERY hesitant for all the reasons Brad mentions above and more to have UGC anywhere near release.
Ironically, I was looking at Wurm Unlimited on Steam yesterday, and thinking "you know, if I didn't really need to know how to code and if the creation tools were really robust, this might be worth trying to do."
I've played some MMOs that had UGC in the form of user-generated dungeons/adventures (using some kind of dungeon builder), and some of the things people did were really, really good. A lot of them were terrible, but the ones that stood out really shined. I'd support a system that allowed community members to create and submit content in this way, and then have it reviewed and voted on by the other members of the community - BUT, it really doesn't work without instancing... or at least, I can't think of a way for it to really scale without instancing.
