Starting off with the easier request, could you have files that fail CRC rehash affected blocks, and if failed remove that block and put it back into downloads. This would be quite nice for those that are using single drives, especially older ones.

My second and more involved request would be to integrate par2(3?) (as opt in) to automatically create par2/3 files to allow repairing (ideally automatically) files affected by bitrot. The creation is already possible via File: shell commands, but completely automating it would be nice
.1% parity should be adequate for most situations, maybe 5% for smaller files