"Terrible" might be a little extreme but it's a little hard to argue that Wikipedia has not seen better days. The moderation culture has seemingly been taken over by deletionists who seem more concerned about some arbritary metric of "notability" than if an article is of high quality.
Plenty statements with citations that don't really support the claims made directly but instead paraphrase the claims in the introduction of some paper (turtles all the way down)
Article size has grown whilst increasing noise to signal ratio (I guess you could call it an opinion)
Influence by certain groups with a selfish interest in editing the content, and more authority given to established editors
Those are the ones that come to mind at the moment
I regularly find Wikipedia entries helpful and factual. How is that terrible?