Here's my product suggestion:
A user should be able to turn swimlanes on and off when looking at their board, as easily as turning filters on and off.
Here's the usecase to support this:
When I'm running standup, and I everyone to be able to see their tasks and subtasks, grouped in swimlanes by Story.
But I also want everyone to understand the overall progress in the sprint, so I want to them to see the progress of the stories across the board.
Ideally I'd like the everyone in the team to do this themselves on a regular basis, rather than just at standup.
Therefore:
Each user should be able to turn swimlanes on and off easily, and without it impacting how the board appears to other users.