Another oldie but goodie!
I can see the attraction here to make it quick and easy to update cards on the kanban board - if someone using trello could share screenshots of what this looks like, that might move this conversation forward. I think ultimately it may be more effort than justified and it would be a very low priority.
We have been adding the ability to show more detail to the cards in the kanban board, so you get an overview and don’t have to click through to see more. E.g. tags,
I think it would be cool if Discourse Tooltips could be supported on kanban boards, which shows you some topic text on mouseover.