Periodically (definable) re-check destination disk space
When pre-allocating multiple torrents for overnight downloading, the destination drive (particularly in the case of a smaller SSD) will fill before all torrents can allocate. This leaves many torrents in a stopped "insufficient disk space" state. These torrents do not start automatically when space becomes available (where completion moving is used).
A periodic free space check of the download destination would make it possible for the unallocated/stalled torrents to resume without user intervention.
This would be particularly useful to those users throttled during daytime/peak hours, where night time downloading is preferable and far more fruitful.