The original developer hasn’t been around the forums or released an update in many months. I can’t speak for him, but I view the project as abandoned unless he resurfaces. There were some PR’s added in the GitHub repo months ago, none were ever approved so I think it’s a waste of time. If it’s for 1 site you might consider forking your own version and adding what you need.
I’ve recently released QuizMaster which is a fork, but also a major rebuilt of WP Pro Quiz. It has about 30 templates, not 100% coverage yet but we’re working towards that goal of all HTML being in templates. It has an override system that works with child themes as well as base themes using the folder YOUR-THEME/quizmaster/ to put the custom templates. There is also a loading filter on all the Views (from the MVC approach) so that you can use your own custom View in place of the original, but that’s a rather advanced approach… usually overriding the templates should do the job.
Moving the HTML to templates instead of view functions was one of the first challenges we tackled. It’s a must-have really, there is a limit to what can be done with only CSS. We’ve also stripped all the !important declarations from the CSS, which was making it extra difficult to style.
