I just tried the "Rebuild Library" function of +iPhoto Library Manager+ from Fat Cat Software (
http://www.fatcatsoftware.com/iplm/) and it worked like a charm. It does take awhile (about 2 hours for my 11GB iPhoto Library) but it retained everything perfectly (including all the metadata), and now the issues with deleting photos, iPhoto not quitting, and all the other weirdness are gone.
iPhoto Library Manager keeps your original iPhoto Library intact and rebuilds to a new library, so you can test the effects safely.
I strongly suggest that anyone who has this issue give it a try. Please note that I have nothing to do with this software; I just tried it and it worked well on my library.