qBittorrent official forums

Maybe a checkbox in Add torrent dialog and Options with "Allow qBittorrent to make subfolders in this save location" to place the subfolder files in the save location if not checked?

Are you talking about creating a sub-folder that is the topmost folder of a multiple file payload? Which unlike uTorrent, qbittorrent/libtorrent does not do this. Any sub-folder that is there is actually part of the payload.

OR a sub-folder for single file payloads? Which again qbittorrent/libtorrent (unlike uTorrent) does not do.

The 'feature' of turning this folder creation on or off exists in uTorrent because it already does behave badly and add this additional top-level folder to ALL torrent payloads, multi-file or single-file, this is what makes it problematic to import completed or partial payloads from a uTorrent/BitTorrent client environment into any other client environment when just using the metadata and existing payload.