Jeff is bugging me about this again, so I guess I'd better do something to fix it. Here's what I'm planning on doing:
So what I'm going to look into doing is a drop-down list of all users currently assigned to bugs in this project, then an option called "Other..." or something like that, which, when the page is submitted is replaced with a widget to let you search for a user (perhaps we can do that with javascript, too, for people who have that enabled), then on second submit is replaced with a drop-down list of users that matched your search.
I'll see if it can become a templating system widget, so it's reusable.
I'm also going to change the permissioning logic so that if you're assigned to a bug, you're also allowed to actually edit the bug. We do that today with submitter: If you submitted a bug, you can edit it.
Comments?
/Lars