The option to have transitions “group” clips together. This could just be a toggle in the timeline panel like the snap tool but where constant powers, morphs etc hold clips together when shuffling them around.

This would be particularly handy when piecing together interview and applying constant power transitions to a string of dialogue, instead of having to zoom out, select the clips which have transitions you're happy with and then move them all you could just toggle the function and bring clips together by moving them all at once.