After adding fields via card layout, for example estimated effort, due date, and assignee, it would be helpful to edit the values directly on the card on the board. So the user could click on the date and a datetime picker appears, users could click on the time and a text box is activated to change the value. This behavior could be extended to any field added to the card fronts via the card layout screen. This would save considerable time when editing single values for issues, rather than having to click on the card, clicking the ... on the right, clicking edit issue and then clicking update issue.

I've attached an interactive pdf to try and demonstrate the concept more clearly.