I agree with you about Lirael's character growth, and about wanting to read about Lirael and Ellimere. I was torn on Sameth's annoyingness; sometimes I sympathized with him (because even if it's annoying in a fictional character, I have totally been that person, although I hope more introverted and non-annoying about it) and sometimes I just wanted to smack him. And I adore older Sabriel and Touchstone; I love happily married adult couples, and they totally were that.

Abhorsen is probably my least favorite of the series, but talking about it now has me wanting to reread it anyway.