So hopefully development hasn't reached a point where it is now inflexible to suggestions. Before release, I would suggest developing the recurrience functionality to a level that is robust enough to meet all the various users needs. For instance, I would definitely release recurrence from completion date option as well as from the more vanilla due date. Maybe start and end date for recurrences. Also, it would be nice to see recurrence options such as 'first/second/third thursday each mo' and other more colorful options.
Another kind of cool feature which I have only seen once from another task management platform would be an 'optional' choice for the item. So if the item has a date, and you get to the date, it will complete itself when it surpasses the due date and passes into overdue. It would be more for items where you want to see it approaching and reminding you of it, but if you don't complete or don't catch it no big deal, cause it checks itself. For example, an upcoming concert, hey you missed it, but you don't have to go into your overdue and check it off it takes care of itself. Another example would be that you could use it for recurring items too, like say a show that happens once a week, so maybe you miss a week, but it completed itself and moved it forward to the next week. I thought this was nice because it removes alot of overhead maintenance when you miss the types of items that you are fine with just pushing themselves forward.