I would agree that you don't have to have read the Clocktaur War books to enjoy Daggerbound, but I'm glad I reread them. Learned Edmund actually grew a lot in those books, so it was good to see where he came from as well as where he ended up.
I must say, Daggerbound really spoke to me. I sooooo sympathized with him at the beginning. Before I retired I also was so tired of fighting people who would only change with a brick to the head. Sometimes you just have to quit and move on.