DO
Handled properly, interlaced formats don't blur anything. Many PC applications don't handle interlaced formats properly, and they will never look right in single frame captures, as you're seeing two separate moments in time.
An interlaced format at 50 fields per second will handle motion better than a progressive format (even of same resolution) at 25 frames per second.
Finally, the 720p streams won't look better than the 1080i ones, because they are being from the latter. The main reason for not delivering the interlaced versions is that PC's not handling them properly. It's better to have one good deinterlacer at the source end than trying to do it at the PC end.
An interlaced format at 50 fields per second will handle motion better than a progressive format (even of same resolution) at 25 frames per second.
Finally, the 720p streams won't look better than the 1080i ones, because they are being from the latter. The main reason for not delivering the interlaced versions is that PC's not handling them properly. It's better to have one good deinterlacer at the source end than trying to do it at the PC end.