I like Well of Ascension the most out of the series because of the territory it explores - it's that moment in any revolution where you seize the control everyone thought you'd never get, and you're immediately surrounded by hostile forces as a result.
Book 3 will give you an interesting excuse for some of Vin's needless self-loathing. But on top of that, it's how someone who has been beaten into submission her whole life rationalizes things - a combination of excuses as to why her life is the way it is (she's not worthy, her enemies can't be defeated, etc.). It's jarring to her to actually be powerful. Her worldview hasn't caught up yet.
"Both of them have had their struggles, yet I don't feel they've felt loss the same way Kell did at the Pits and before, and he had no one to save him and make it better the way Vin had."
This will be foremost in their minds going into Book 3.
"She's the most illogical of all of Brandons characters."
Wait 'till you meet Wayne.