If they're not being played much, that means that changing the content won't have much effect - none at all, unless a lot of people are opening it in html mode, looking it over and backing out. My quiz play numbers seem to depend mostly on the category - some of the most highly-rated ones are also the least played, because Geography just doesn't grab the interest of as many people as, for example, movies. Even in a popular category, a quiz on a specific topic (one movie, one book , etc.) will only attract those who are familiar with it.
About the only change that is likely to lure in more players would be a change to the introduction. I don't think you need to involve an editors for that, but beware! If you accidentally make an entry that is over the allowed number of characters, either in the introduction or in the summary box at the end, the quiz will be unceremoniously yanked offline, and you will have to fix it then contact an editor with an apology for needing to have it checked again to go online. I only did that once in adding an acknowledgment of the player who had proposed a commission title, and now do a careful count in Word before replacing the summary box!
(Editor in Humanities, Religion, Literature and Books For Children)
That's all, folks!