Here are the things i wish that Bethesda had done for settler assignment:
To assign a settler to a task: Would be nice if it could be done in workshop mode as currently enabled, OR in regular mode. In either mode, it could look something like:
-Click on a settler to talk to them, and get an "assign" button choice option if they are unassigned (or get an "assigned to: [task]" message if already assigned). Choose that option, and get a list of everything in that settlement that is currently built but not yet assigned to anyone. Select something from the list to assign them (no need to walk clear across your settlement to assign if your settler isn't standing near it at the time).
OR
-Click on an assignable item, and either see an "assigned to: [name]" message or get a button option to assign, with a list of settlers who are not yet assigned (or just able to click an option to randomly assign any unassigned settler to that task)
To tell if a settler already has an assignment/what their assignment is: Would be nice if the game could just auto-equip a settler with a "uniform" if assigned (whether that is a special hat, a shirt, a colored bandana, whatever!), and if each uniform were unique to that particular task assignment. That way you can tell at a glance who is assigned and who isn't, and what each person's assignment is.
I also don't know how easy or not easy it is to unassign someone from a task right now (because I haven't had to do that yet), but the above options could also work. In the assignment options (when clicking on a settler or an assignable item that is already assigned), one option could be to unassign (or reassign to a different task).
I am fairly early in my playthrough, so if any of these are actually possible (and I just haven't figured them out yet), please let me know! As far as I could tell, none of them are, but I may have missed something.