#Wikipedia's biggest challenge. What amazes me most in all this is the lack of credible suggestions to alleviate this. The only one I find is to give kittens to people. Not a good idea as kittens become quite rapidly sexually mature and have this nasty habit of becoming octamoms.
It is hard to enter Wikipedia because of the increasing levels of "required" sophistication. This makes Wikipedia more high brow, reliable, wordy and both hard to read and edit. By making quality a priority, Wikipedia is no longer the inviting community it once was. With this change the number and size of illustrations vis a vis the number of words has gone down, the number of foot notes has gone up and developing new templates is a too much for most of our best.
With the number of participants and the quality level a balancing act, there are things we can do to motivate people to stay with the program. The most obvious thing to do is motivating people. As obvious it is to make participating less complicated. There are technical solutions like the Sentence-editing tool by Jan Paul Posma that make editing a lot easier...
An other big group of potential editors is left disenfranchised because they do not have the support for their language on their device. Many of their issues are solvable, it is solvable without a need for more studies or reflection teams. It is solvable when usability and accessibility is truly a primary goal for this year.