Deletionism - focus on fewer articles and make them better; less-edited articles are likely more inaccurate: it's better to be uninformed than misinformed.
Ambiguity, in the mostgeneral sense, is the last thing needed on Wikipedia. When presented with facts, there should be as few interpretations - "readings" - as possible for the reader.
Opposition to political Wikiprojects, as I believe they incite canvassing of ideology; a hindrance on a free encyclopaedia.
All statements labelled "citation needed" should be removed immediately.
Encyclopaediae should act like almanacs; they should be factual, plain and dispassionate, but informative.