Normally you'd have a template for specific types of pages.
It would be awesome to have a standard one for API functions, then that way if people have useful info to add, they can do so.
Take a look at some wowwiki pages for example (two with varying amounts of useful info):
http://www.wowwiki.com/API_GetCategoryInfo
http://www.wowwiki.com/API_SendChatMessage
Even just as simple as specifying sections and navigation would be handy. In the example above, sections could be: Syntax, Parameters, Results, Details, Example.
You could get fancy and divide things up into sections, but not sure that's really needed.
edit: Whilst there is a
function for defining templates in mediawiki, you don't need to go as far as doing that. You can just specify, "please copy this text for your page before starting to edit" or something.