Checking out more of Richard Linklater’s work is also highly recommended.
Waking Life (2001)
Philosophy and dreams combine for an enlightening journey. It’s a good rewatch if you’ve not seen it in a long while.
Before Sunrise (1995), Before Sunset (2004), Before Midnight (2013, I haven’t seen this one)
Ethan Hawke and Julie Delpy have beautiful explorations of love and the human condition.
Anticipating Book > Film (musical?) > Play/Musical
Hopefully, what they padded the movie with is the contents — the politics — of the book. As u/MrVilliam said above: