this is probably a ways off, but I’d like a good, highly-customizable search function. for example, searching for releases by a particular label genred with moe song, or songs that have both Brony and metal as tags (with the option to include subgenres or not)

RYM has vaguely similar functionality with their Charts feature and all the filters you can use, but they're all gonna be sorted by rating (or other criteria, see the "Top" dropdown)