Changes to the default width for a column should be PER USER, NOT GLOBALLY SHARED.
Every time I load my board, the size of the Task Name column changes. I can only assume this is the case because any change to the size of the column affects all users of a board view. This is super irritating, because when I size the column so that it fits comfortably on my tasks (which tend to have small names on my small laptop screen) it is equally obnoxious for my colleague with long task names and a widescreen monitor.