Don't know if Microsoft watch this group at all, but here goes:

1) Allow dragging tag to picture as well as picture(s) to tag
2) "Thumbnails with tags" view needed
3) Deleting a tag should NOT remove it from all pictures. Sometimes you just
want to tag some pictures for an Event, e.g. Concert May 2006, and then
delete the tag because you'd never assign it again
4) Proper grouping of tags, e.g. a People tag containing Jim, Robert and Sue
should not be a real tag, just a heading.