thanks for getting back to me.
there are some good points you make there. A button or switch to go into column edit mode would be most appealing to me I think personally. I like that idea and I will certainly have a play with it.
as for adding cards, where do you think this should live? some people have suggested at the bottom of columns. This does sound good, my only problem is that what if the user has to scroll to find this functionality? with an icon at the top of the column this is clearer IMO, if columns had a mode then I guess the remove column icon wouldn't be visible at the same time as the add item icon. I'd value your opinion on this part of the UI.
Thanks again for your feedback and input!