Pride and Prejudice could absolutely be seen as a plea for good sense if the reader viewed it as a morality tale from the point of view of two sisters who make very different choices for their futures. The novel is a classic tale of 'good sister, bad sister.'
Elizabeth Bennett and Lydia Bennett are both afforded the same indifferent upbringing, but the most notable difference between the two is Elizabeth's conscientious choice to employ good sense and moderation in her choices, whereas Lydia is characterized as being a flighty, ill-mannered girl with very little self-control. Even her father recognizes her as one of the "silliest girls in England." Lydia's choice to run off with Wickham scandalizes her family and puts the Bennetts into a very difficult place, having to deal with the shame of her elopement. Her lack of good sense results in an unhappy, unfortunate marriage to George Wickham.
Elizabeth Bennett, on the other hand, is valued by her peers as a woman of good sense and understanding. Her good choices and good sense are rewarded in the end as she makes a most advantageous marriage to Mr. Darcy.