Well, I finished it last night. What a rich experience it has been to read it. A couple of thoughts:
"He distrusted her affection, and what loneliness is more lonely than distrust?" That sums him up for me - for all the distress he caused Dorothea, what a miserable life he gave himself in his inability to trust and to give and accept love. I did feel sorry for him, though it was a relief when he died!
Another really good statement from earlier in the book, concerning Casaubon and Dorothea: "There is hardly any contact more depressing to a young ardent creature than that of a mind in which years full of knowledge seem to have issued in a blank absence of interest or sympathy."
"He had begun to distinguish between that imagined adoration and the attraction towards a man's talent because it gives him prestige, and is like an order in his button-hole or an Honourable before his name."
What a sad and unfulfilled life he led too. But can we be too harsh in our judgement of Rosamond? She was a product of her family, and of being petted and indulged all her life simply because she was beautiful. She was shallow, vain and manipulative because she thought she was the centre of the universe and deserved whatever she wanted. But she did do the right thing by Dorothea and Ladislaw when it could all have ended in grief, so she did respond to Dorothea's goodness and generosity of spirit.
We are left to assume that Ladislaw and Dorothea had a happy marriage. I suppose we could feel that Dorothea should have remained single and done "good works" with the wealth, but how free was she to do that in reality, given the status of women at the time? At least she was able to decide to marry him despite the disapproval of various people.