Loop overlay mode.
When mode is activated, if you are looking at loop start/end, corresponding waveforms are overlayed with different color.
This is less pressing with technological advancements such as crossfading, but personally, I'd rather butcher as little as possible.
Caveat: cannot see properly if at the very start/end of sample.
For this I propose: split view. Draw another sample view in line with the real sample view, but dedicated to loop viewing, own zoom, only activates with mode.