JBroadway said: "I haven’t looked through a list (maybe I will later and amend), but Jagged Little Pill immediately jumped to mind. One of the worst pieces of writing I’ve ever seen, let alone worst musical books, let alone Tony winning-musical books."
For the record, I did end up looking through the list of winners in this category: Out of the 56 winners, there are only about 11 that I'm not familiar with (i.e, I've never seen the show in any form, so I can't comment on the book - even if I know the story, broadly, from listening to the score). Of the remaining 45, I can confirm that Jagged Little Pill is, without a doubt, the worst of the bunch IMPO.
As for Tootsie, I remember many people at the time seemed to feel that Tootsie had the superior book, and deserved its win. I disagreed, and still disagree. I tend to think that it won the award mostly for its jokes, which is all well and good if the award was called "best jokes that take place during scenes of spoken dialogue." I'll admit that Hadestown's book is a little messy, and I can see why some people preferred the book for Toosie, which was somewhat more traditional, and therefor a bit more cleanly structured. But to me, Hadestown's book is BY FAR the more impressive achievement in storytelling overall. Not even close.
BETTY22 said: "I sooooooo admire book writers"
I admire book writers in theory, in the sense that it's an extremely difficult job, and most people undervalue the importance of the book. But it's hard for me to say that I truly admire the actual output of "book writers" in general, when 90% of musicals these days have a bad or mediocre book.