(In all seriousness, I'm always interested in hearing people's suggestions and learning about pain points that I haven't experienced myself. So if you or anyone else have ideas about what things should be on my list, there's no harm in letting me know, either by PM or by starting/bumping a Meta topic. I've found that tackling things in priority-order isn't really an efficient way for me to work, so I appreciate having a mixture of tasks that I can put my shoulder to semi-randomly.)
#1, 2, 3, ... 99 on my pain list: have a basic API so that we don't need to scrape e.g. user profiles continuously all the time and instead could just pull recent changes... would be easier on the site, on scrapers, and wouldn't break any time the UI changes. Obviously authenticated and throttled and whatnot.