As the title suggests, I'd love to drag columns around to quickly organize clips.
For my workflow, I utilize the columns heavily, both for composition and for groups. I also enjoy laying my content out in a linear way when it's possible, so the ability to move an entire "look" for a song or portion of a song/event would be huge, so that way I'm not copy/pasting whole columns or fiddling with a bunch of dragging individual clips.
Dragging a column on top of another could swap columns, meanwhile dropping them in-between columns could simply move and insert the column into another position.