Editing is all about balance.  While it is important to correct obvious flaws in structure and punctuation, it is also crucial to uphold the author's own voice and not leave it swamped in grammatical drudgery.  As an editor, I try to maintain the feel and flow of the article while paying close attention to detail.  Educated in the British grammar school system, I have a love of the English language and am quite meticulous by nature; however, in most cases, my work is merely a suggestion rather than a mandate.  I like to operate by establishing a dialogue between myself and the author, so that in the end the work demonstrates all the original ideas, all the original passion, with just the gentle touch of a guiding hand.