Austen definitely had a soft spot for Mr Willoughby – we almost feel sorry for him at the end. Despite seducing Eliza, abandoning Marianne and marrying Miss Grey for her money.
Here is the end of the final meeting of Elinor and Mr Willoughby
He held out his hand. She could not refuse to give him hers; he pressed it with affection.
“And you do think something better of me than you did?” said he, letting it fall, and leaning against the mantlepiece, as if forgetting he was to go.
Elinor assured him that she did; that she forgave, pitied, wished him well — was even interested in his happiness — and added some gentle counsel as to the behaviour most likely to promote it.
Come to think of it, we feel sympathy for Henry Crawford too.