This would require work in both MLT and Kdenlive, but multicamera editing support would be very nice.
Basically would need to support reading and parsing ancillary data containing time code, and then locking their location in the timeline accordingly. Kdenlive would also need to provide the option to set what time the timeline timecode starts at.
Would also need to support the same functionality when importing audio only tracks with timecode like Broadcast Wave, Wave64, etc.
Same goes for rendering: needs the option of render with embedded timecode.