In T6027#135704, @isfs wrote:

Would it perhaps be simpler if instead of developing a "Change columns" UI, actions can be added to move columns, something more along the lines of what I mocked up for T9280, i.e. a simple action with two parameters, rather than a monster action with parameters for all existing boards?:

If you want to move the task on multiple boards (which I imagine is relatively, if not absolutely rare) you would just add multiple actions. The order of the actions is clear, even if not mutable.