Really, this is one of the things which makes me most reluctant to review posts. I practically never find the stackexchange site which I believe is most appropriate for migration on the automatically-generated list of migration options. And I can't mark the question for migration unless I select something on that list. Clearly, it would be counter-productive to mark it to be migrated to the wrong site. So I end up frustrated and the ill-placed question remains where it is.
All that is needed is to add an "Other" field which accepts a stackexchange site. In addition to lowering my frustration level, this would also give SE developers some feedback on the autoatically-generated alternative site lists, which might result in improvements. So an all-round win.
