::::::Here is my two cents: passive voice is undesirable for two reasons 1) it weakens the quality of the text. That is the general rule for all sorts of writing on and off Wikipedia  2) there is a common flaw in Wikipedia editors who prefer the form "Smith is considered to have been a pioneer in the field of ABC" Instead please write "Smith was a pioneer in the field of ABC".  The passive version posits the existence of unknown unsourced mystery people who did all that the consideringWe do not know who considered,  when they considered, or why they considered. That said, passive voice can be occasionally used without too much trouble (Such as this statement in our article: "and his strategies are featured in the military history textbooks" since it is very obvious that history textbook writers are doing the featuring.