Sorry to wish against you but I hope Explorer never gets them, not even as an option, because I think they are a garbage idea for browsing files or anything else since they're too busy and constantly make you change your focus.

They're bad for browsing, I agree. I do a lot of file management and reorganization across network drives, and it would benefit me by immediately exposing one or two directory levels above a file location for drag and drop simplicity. Multiple windows or tiling tabs in Windows explorer could accomplish this as well, of course.

win+right, ctrl+N, win+left, alt+up+up