The LW 5.3.0 Beta now prevents files known to be bad from even beginning to be downloaded. The beta was just released a day or two ago.

Yes a number of people have complained about the video files being lossed. But they would not have been deleted unless the file's download-hash matched up with known bad files.

There is always this option Downgrading to LimeWire 4 from 5 & resuming incomplete downloads.