I've been editing for a couple years now. The vast majority of articles beyond stub class are great. The ones that get brought up on AN/I or ArbCom or MedCab are generally on subjects that people hold very strong opinions on. For example, the first article I became very involved with was
http://en.wikipedia.org/wiki/Provisional_Irish_Republican_Ar.... When I came to that article, it was in the middle of an edit war between Republican and Unionist factions. Each wanted the article to reflect their POV, so there was much arguing over whether the IRA "caused"/"was responsible for" X deaths, or they "murdered" X people. Similarly, many editors wanted to be sure that the page clearly showed they were a terrorist organization. WP:TERRORIST specifically prohibits the labelling of an organization as such, so instead those editors fought to have the article state that other organizations had labelled the IRA terrorists, etc.
That's generally how it goes on the sensitive articles. The three main areas of political debate on Wikipedia are Israel/Palestine, Eastern Europe, and Northern Ireland. There have been perennial edit wars, and many ArbCom cases. There have been mailing lists and drives by external organizations to infiltrate the ranks of Wikipedia so as to have their viewpoint expressed. There are admins who have acted improperly and had their status stripped, and there are others who have done the same with impunity. Basically, it's a shitstorm.
It also affects less than 0.001% of articles on Wikipedia. As far as articles with promotional points of view, recognize that many companies will actively edit the article on them, and it takes diligent community members to counteract their whitewashing. That's why WP:COIN and other noticeboards exist. Similarly, some people will edit an article with the goal of making the subject of that article look bad. The remedy is the same as for whitewashing: a neutral community member needs to fix the article.
The problem is that there are millions of Wikipedia articles, most of which the average editor will never come across. The community is big, but not that big. We will never make Wikipedia perfect, although I have some ideas for making it more so.
In the end, the best you can do is fix problems as you come across them. If you notice any patterns that you think could be identified algorithmically, consider writing a bot or, if you are unable to do so, approach one of the prolific bot writers like MZMcBride with your idea. Otherwise, just keep plugging away, and realize that the dramawhoring that characterizes the Wikipedia community is largely absent from the articles themselves.