One *big* problem we have now is: Wikipedia has won. Wikipedia is the encyclopedia anyone actually consults, ever. Wikipedia now defines what an "encyclopedia" is in popular conception.
So we don't have any tail-lights to chase. What sets our direction?
Well, this is now completely and utterly off topic, but since I'm here... I _think_ maybe I've known the answer for several years now, but I still don't really know how to communicate it. But since you asked---
The most exciting thing I've heard of is kinda hard to explain in English-- at least it's hard for me to explain it. It can be described in geekspeak by saying "How would Wikimedia be different if it had been made after Git?" Go ask the Free Software people that question and watch their faces light up with possibilities. To other people you can say "What if Wikimedia projects were less like a website and more like the internet itself?" and they'll get very interested, even if they don't know precisely what you mean.
Our "business model" is to take the lessons of Free Software and apply them to the challenges traditionally faced by librarians and educators.
In 2002, we sort of 'forked off' from the 'mainstream' Free Software movement, and this 2002ish model of revision control is the model we use in our wikis. Since 2002, literally some of the best minds on the planet have been working on the question of how large groups of strangers can work together to create documents when they don't all want the exact same finished product. The lessons they've learned, and the tools they've created, are truly mindblowing.
Imagine if virtually every editor's computer had copies of whole chunks of Wikimedia projects, starting first and foremost with your own contributions to the projects. Each editor could effortlessly, automatically, seamlessly share their contributions with the whole world. A users could create a whole new 'project' without using any Wikimedia resources at all-- not a single dime. If a new project was popular, it could be seamlessly and automatically shared with the entire world, again, at no expense to the foundation. "Bad" projects would get weeded out because no one would share them, while "good" projects would rise to the top automatically. All with zero external oversight, zero external support from the foundation.
On such new model projects, two editors could simultaneously edit the same article without those pesky software-triggered edit conflict warnings that interfere with their editing. Interested editors could have edit wars if they want, but edit wars would not wipe out a third party's contributions the way they do now. Each editor controls and hosts their own private 'sandbox versions' of the articles. Writers could just write, individually or collaboratively, as they chose. Their contributions would only get shared if they were popular, their contributions might or might not wind up in a version directly hosted by the foundation, but either way, their contributions could be easily and widely shared so long as people were willing to donate the space and bandwidth of their own computers to share it.
On new model projects, there would never be any "one" version of such a project at any fixed time. Instead, the version of the project at a given time can vary, depending on who you ask. If you ask our canonical servers, we'll give you 'the' one answer-- but if you want to ask your roommate's computer instead, you can see if he knows something about the subject that our server's consensus does not.
A fun bonus of this would be that it would instantly set a fire to independent development of the mediawiki software and its extensions. Once hosting was distributed, new features would become distributed too. If I want to add a feature to a "new model" project, I need only convince my own computer, I don't have to build it and then hope I can convince strangers that it should be used.
It's not my idea, I believe it's been independently suggested at least five different times that I know of. But it's a HUGE step that would require a big, bold push from developers and thus potentially a large initial commitment from the foundation to spur development of such a thing. That commitment might not be huge in terms of resources-- a few professional lead developer-coordinators, perhaps. But it would require some courage, leadership, and a vision to rally volunteer developers around. If you visibly agree to it being built, an amorphous 'they' will likely show up to actually build it for you, free of charge. It would will radically change things for everyone the instant such a tool is actually created.
Such a wiki is inevitable, I just hope we can be the ones to develop it.
Alec