I've seen a lot of information here being ridiculed since it came from Wikipedia, and hence not accurate or reliable, often with the commenters having better sources of their own.

This is covered in the FAQ a bit - I think /u/gingerkid1234 covers all the essentials in Why Wikipedia Is Not A Source, but it goes a bit beyond inaccuracy and the particular editorial culture of that site. The long and the short is: you shouldn't rely on encyclopedias as primary, or even necessarily secondary sources. They're a good starting point for someone that knows nothing about the subject to get an overall impression, and maybe to find some sources to follow up on it. If you have nowhere else to start in your research, you could look at Wikipedia and read the article and follow the citations and go from there. But Wikipedia (and any encyclopedia, really) is not an authority unto itself - there is no (or not supposed to be any) original research or analysis in those articles; it's all regurgitated and condensed from other, better sources - and, as mentioned in the FAQ, not always well. Posting a link to Wikipedia as an answer, even as a partial answer, to a question is lazy and bespeaks a lack of specialized knowledge on the subject - and specialized knowledge is pretty much what askhistorians is here to provide.

Shouldn't we be trying to improve Wikipedia if we find historical articles to be biased/incorrect?

This dips into the broader question of "Shouldn't we make the world a better place/add to the sum of human knowledge?" and the thing is - not everybody has the time or inclination to spend their day trying to expand or clean up Wikipedia articles (or, for that matter, answer questions on r/askhistorians ) - and that's fair. You can't force people to do that kind of thing for free, people have to actively choose to do it - and some folks do! There are users on askhistorians that cut their teeth in the endless edit wars on Wikipedia, and still wade grimly into the struggle today, navigating the cliques and the IP blocks and all the rest of it - and more power to them. Others just don't have the patience - or the desire - or the knowledge of wiki-script - to contribute in that manner. That's their prerogative, and arguably that's how it should be, because other folks add to the sum of human knowledge by researching, writing, presenting, and publishing articles, essays, theses, blog posts, books, dissertations, documentaries, and presentations...or even their own wikis. There is more than one way for the folks of AskHistorians to contribute, and I don't really fault any of them for choosing to do it in a way other than trying to edit Wikipedia.

I know the admins and users on Wikipedia these days are not very cooperative and it has way too many rules, but I still think it should be something that /r/AskHistorians as a community should do.

If you want to make that your special project, Ghost be with you. As a community, however, AskHistorians has a different purpose than Wikipedia - trying to provide specific, well-researched answers to specific questions rather than the general overviews provided by individual articles - and while it might be an encouraging follow-up to some answers to incorporate those sources and citations into a Wikipedia article to make it better, many times the questions and answers on AskHistorians are out of scope for the general nature of Wikipedia.

Wikipedia admin here. Generally I agree with AncientHistory however I wish to add that one of the things in theory that should differentiate askhistorians from wikipedia is that askhistorians allows experts to have opinions.

Experts tend to have committed opinions as a side effect of studding an area for an extended period this can cause problems on wikipedia (see https://en.wikipedia.org/wiki/Wikipedia:No_angry_mastodons ) but is hopefully more welcome on askhistorians as long as those opinions can be supported.

Just as an FYI, this isn't a META thread -- META threads are about the subreddit itself, not about sourcing or third-party websites. Just so you know why it's not flaired as META :)