Why do readers initially find Mr. Bennet more likable than his wife? Does Austen ever attempt to change readers’ opinion of the Bennets? Which characters does Austen seem to favor?

Readers tend to find Mr. Bennet far more likeable than his his wife because he is, but that certainly doesn't make him a better person, as we find out along the way. Mr. Bennet is intelligent, witty, and has a knack for acutely observing what's going on around him. His character is funny and entertaining, but much of that humor is at the expense of his wife.

Bennet is the prevailing head of a household full of women. He is surrounded by silliness, and he tends to enjoy the solitude when they're away from home.

Austin seems to attempt to explain the Bennet's relationship (I wouldn't necessarily say to change our opinion)when she flashes back to allow us glimpses of their courtship. In a time of arranged marriages, Mr. Bennet chose his wife for love (or lust as it was), ignoring her silly behavior and focusing on her beauty. Unfortunately, beauty doesn't make a marriage and five daughters later.... the couple really have nothing in common.