I really don't have a problem with the bookmark interface, but the Firefox guys do get a lot of complaints in that area. A new interface is going to be introduced in later versions: it was originally planned for 1.0, along with a bunch of other things, but they had to drop them in order to actually get a realistic release date.
There ARE some bookmarks extensions that add the type of usability you seem to want, but I agree the interface could be better. Still, it's quite workable for basic use.
"There ARE some bookmarks extensions that add the type of usability you seem to want,"
If you know the names of them then let me know.
Thanks.