I frequently hear complains from people about individual Wikipedia pages but most of the people who complain only complain outside of Wikipedia. Wikipedia is inherently democratic. If you read a Wikipedia article and think it's very problematic, take five minutes and write about why it's problematic on the talk page of the article.
Wikipedia is an important part of the commons. If you think from an EA perspective those five minutes (or even more if it takes you time to search for sources) have a good chance of being time spent with a good EA return.
While recruiting people outside of Wikipedia to individual pages to engage in discussion goes against Wikipedia's rules, simply engaging on Wikipedia and voicing your opinion is helpful. It makes it more likely that consensus on the article shifts in the right direction.
I agree that people should edit a Wikipedia article directly or discuss on the talk page instead of complaining about it elsewhere. Leaving a comment on the talk page can be a quick way of helping shift the consensus for a controversial topic. In my experience though, unless it's a very popular page, it's often the case that when someone leaves a comment on the talk page describing overall changes that they want to be made, no one will respond and no changes will be taken. Or someone responds with an agreement or disagreement, and nothing happens. Thus, especially if it's not a controversial change, be bold and directly edit the page yourself. The Visual Editor makes it very easy to make edits—you don't need to know the wiki markup syntax. Make sure that your edits are balanced (so the article has a neutral point of view) and all claims in your edit are backed by citations to reliable sources. Watch the page so you can get notified for further changes to the page, such as if your edits are reverted in part or in whole in the coming days. If they are reverted and you disagree with those changes, politely discuss it on the talk page and ping them with {{Reply to|username}}. If it's a semiprotected page or extended confirmed protected page that newbie editors don't have permission to edit, you can leave an edit request on the talk page detailing the concrete changes that you want to be made.
I agree with this advice.
I think a simple way to get involved with Wikipedia is to "adopt" an article on an important topic you are familiar with but which is currently covered inadequately. This will allow you to see how your changes are received, develop a relationship with other editors who contribute regularly on that page, and experience the satisfaction of seeing the article (hopefully) improve over time in part thanks to your efforts.