In certain ways, Wikipedia has become less useful, the more that the community has cracked down on unsourced information, or has enforced a strict and exclusive understanding of external link guidelines.
Early on as a user, about 2005, I had embarked on a low-carb diet, and I wanted to learn about it. I looked it up on Wikipedia,
Low carbohydrate diet. and the article was okay, though full of polemic. Listed in the external links was an on-line forum,
lowcarber.org. I followed the link and found a forum where the general public was discussing low carb diets and sharing experience, but there were also experts, published authors, including some who were skeptical about the diets, or who would at least question extravagant claims. Reading that forum, checking the research, etc., brought me up to speed on the topic quickly.
However, at one point, someone listed his own web site in the external links. It was taken out (properly). He revert warred over it. And when he couldn't keep it in, he removed lowcarber.org. "Fair is fair," eh? And he revert warred over that. Finally an admin showed up, looked at lowcarber.org, and decided that, since it has advertising, it was not a proper external link. At that point, to me, admins looked like gods, only stupid ones.....
I had no clue at that time of how to do anything about it. I didn't need it for myself. Later, when I did learn enough about the process to know how to move beyond such a decision, I could have done something, but ... I always had something else to do. If I cared enough, I could still try to fix this. There are now no external links.
The current article itself is better, and there are some excellent books listed for further reading, especially Taubes, but no internet resources, which reduces the usability greatly.
I use Wikipedia all the time, to get a quick read on a topic. However, if the topic is controversial, and especially if the controversy among editors has led to the exclusion of minority position external links, it is no longer useful for depth. There would be simple fixes, but ... the people who might work on those often have been blasted away, instead of being channeled into what I called the "backstory." ArbComm, with Cold fusion, suggested the development of a FAQ or the like in Talk space, but ... the pseudoskeptics don't think that the topic is worth the effort, they just want to keep the "fringe" out, and those who'd work on it have been heavily discouraged and disgusted.
Wikipedia, to actualize the fundamental neutrality policy, needed to facilitate true consensus process. Jimbo seemed to understand this at one time, he wrote some excellent stuff about it, but he was very short on how to actually accomplish this. It takes a lot of discussion. And the community had no patience for real discussion. To avoid deep discussion by a few, the focus was on quick textual decisions, by a rough kind of majority rule (the majority of those who care enough to revert, and who are present enough to notice). That led to the endless cycle of new "fringe" editors showing up and trying to implement what was obvious to them! These "fringe" editors created work for the maintaining cabal, so, of course, for their own efficiency, they would act to exclude them, instead of seeking consensus. And the community mostly did nothing, and the WMF did nothing. So the merry-go-round continued and continues.
Short-term efficiency was in conflict with long-term efficiency.