It would be amazing to have functionality for multiple checkboxes per line. My primary use case would be for tracking things that need to be done multiple times in a week/month, but not necessarily as a repeating task. I work as a sales rep and need to visit all of my accounts each month, but some need to be seen every week and some only need to be seen once per month. I would love to be able to have a monthly template that includes all of my accounts with the number of check boxes on the line that corresponds to how many times I should see them that month, and allows me to check off every time I visit, with the line being fully completed and stricken through when all check boxes have been toggled.
Other use cases would be habit tracking, giving something a score out of 5 or ten (personal movie reviews), lists that need multiple reviews (i.e. writing a rough draft of an article would be the first check box, review is second, and publish is third).